Ford & Lincoln DTC Code List

Codes listed

155

searchable definitions

Systems covered

engine, trans, network

Brands

Ford / Lincoln

Tune-related codes

flagged with tuning notes

Read this first: Ford engines use a mass airflow sensor as their primary load input, so the P0101–P0104 MAF family is the first place to look after any intake change. Ford also uses its own P1xxx range — codes like P1000, P1131 and P1260 mean nothing on another brand, which is why generic code lists get them wrong.

Search the Code List

Code	System	Definition
P0100	Air & Fuel Metering	Mass Air Flow Sensor Circuit General fault in the mass airflow sensor circuit — the ECM cannot trust its primary airflow input.
P0101	Air & Fuel Metering	Mass Air Flow Sensor Performance Reported airflow does not agree with what the PCM calculates from throttle position, RPM and manifold pressure. Tuning note: The most common code after a cold-air intake on a Coyote or EcoBoost. The MAF transfer function has to be rescaled for the new tube diameter or fueling is wrong across the whole range.
P0102	Air & Fuel Metering	Mass Air Flow Sensor Circuit Low Input MAF signal is lower than the valid range for current conditions. Tuning note: An over-oiled reusable filter contaminates the MAF element and makes it read low. Clean the sensor before rescaling anything.
P0103	Air & Fuel Metering	Mass Air Flow Sensor Circuit High Input MAF signal indicates more air than the engine could physically ingest. Tuning note: On a boosted Coyote or a big-turbo EcoBoost the stock MAF curve runs out of range. Rescale the transfer function or move the calibration to speed-density.
P0104	Air & Fuel Metering	Mass Air Flow Sensor Circuit Intermittent The MAF signal drops out or spikes intermittently. Tuning note: Usually a connector or a poorly fitted intake tube letting the sensor see turbulent air.
P0106	Air & Fuel Metering	MAP / Barometric Pressure Sensor Performance The pressure sensor reading does not correlate with throttle position and engine speed.
P0107	Air & Fuel Metering	MAP / Barometric Pressure Sensor Circuit Low Sensor circuit voltage below the valid range — open circuit or unplugged sensor.
P0108	Air & Fuel Metering	MAP / Barometric Pressure Sensor Circuit High Sensor voltage exceeds the valid range for the sensor's rating. Tuning note: Boosted builds outrun the stock sensor range. A higher-range sensor needs its transfer function entered in the calibration.
P0111	Air & Fuel Metering	Intake Air Temperature Sensor 1 Performance IAT reading is implausible compared with coolant temperature and ambient conditions. Tuning note: EcoBoost engines pull timing hard on charge temperature. A relocated or slow-responding IAT2 sensor costs real power.
P0112	Air & Fuel Metering	Intake Air Temperature Sensor 1 Circuit Low IAT circuit voltage low — the PCM reads an impossibly hot intake charge.
P0113	Air & Fuel Metering	Intake Air Temperature Sensor 1 Circuit High IAT circuit voltage high, typically an open circuit.
P0116	Air & Fuel Metering	Engine Coolant Temperature Sensor Performance Coolant temperature does not change as the PCM expects during warm-up or operation.
P0117	Air & Fuel Metering	Engine Coolant Temperature Circuit Low ECT signal voltage low — an implausibly high coolant temperature.
P0118	Air & Fuel Metering	Engine Coolant Temperature Circuit High ECT signal voltage high, usually an open circuit or disconnected sensor.
P0125	Air & Fuel Metering	Insufficient Coolant Temperature For Closed Loop The engine did not warm enough to enter closed-loop fuel control in the expected time.
P0128	Air & Fuel Metering	Coolant Thermostat Below Regulating Temperature The engine failed to reach expected operating temperature within the expected time. Tuning note: Standard after a low-temperature thermostat. Lower the warm-up threshold in the calibration or the light comes back every cold morning.
P0131	Air & Fuel Metering	O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1) Upstream oxygen sensor on bank 1 reports a persistently lean signal.
P0132	Air & Fuel Metering	O2 Sensor Circuit High Voltage (Bank 1 Sensor 1) Upstream oxygen sensor on bank 1 reports a persistently rich signal.
P0133	Air & Fuel Metering	O2 Sensor Slow Response (Bank 1 Sensor 1) The upstream sensor is switching too slowly to control fuel accurately.
P0135	Air & Fuel Metering	O2 Sensor Heater Performance (Bank 1 Sensor 1) The upstream oxygen sensor heater is not reaching operating temperature in the expected time. Tuning note: Long-tube header installs with stretched or spliced O2 extensions cause this constantly.
P0136	Air & Fuel Metering	O2 Sensor Circuit Malfunction (Bank 1 Sensor 2) The post-catalyst sensor on bank 1 is reporting implausible values.
P0140	Air & Fuel Metering	O2 Sensor Circuit No Activity (Bank 1 Sensor 2) The downstream oxygen sensor signal is not changing at all. Tuning note: Appears when rear sensors are removed for an off-road pipe without disabling the rear O2 monitors in the calibration.
P0171	Air & Fuel Metering	System Too Lean (Bank 1) Long-term fuel trim on bank 1 has hit its positive limit — the PCM is adding fuel to compensate. Tuning note: After injectors, a MAF change or a blower install, fix the injector and airflow data instead of letting fuel trims carry the correction.
P0172	Air & Fuel Metering	System Too Rich (Bank 1) Long-term fuel trim on bank 1 is at its negative limit — the PCM is pulling fuel out. Tuning note: Larger injectors with stock injector slope and offset data produce this every time.
P0174	Air & Fuel Metering	System Too Lean (Bank 2) Long-term fuel trim on bank 2 is at its positive limit. Tuning note: A lean condition on one bank only means a bank-specific cause — an intake leak, a weak injector, or an exhaust leak upstream of the sensor.
P0175	Air & Fuel Metering	System Too Rich (Bank 2) Long-term fuel trim on bank 2 is at its negative limit.
P0181	Air & Fuel Metering	Fuel Temperature Sensor Performance Fuel temperature readings are implausible for current conditions.
P0190	Air & Fuel Metering	Fuel Rail Pressure Sensor Circuit Fault in the fuel rail pressure sensor circuit.
P0191	Air & Fuel Metering	Fuel Rail Pressure Sensor Performance Measured fuel rail pressure does not match the commanded value. Tuning note: On direct-injection EcoBoost and GT350/GT500 engines this is the classic sign that fuel demand has outrun the pump. Log rail pressure before adding power, not after.
P0193	Air & Fuel Metering	Fuel Rail Pressure Sensor Circuit High Rail pressure sensor voltage above the valid range.
P0201	Air & Fuel Metering	Injector 1 Circuit Electrical fault in the cylinder 1 injector circuit. Tuning note: Injector numbers follow cylinder order, not firing order.
P0202	Air & Fuel Metering	Injector 2 Circuit Electrical fault in the cylinder 2 injector circuit.
P0203	Air & Fuel Metering	Injector 3 Circuit Electrical fault in the cylinder 3 injector circuit.
P0204	Air & Fuel Metering	Injector 4 Circuit Electrical fault in the cylinder 4 injector circuit.
P0205	Air & Fuel Metering	Injector 5 Circuit Electrical fault in the cylinder 5 injector circuit.
P0206	Air & Fuel Metering	Injector 6 Circuit Electrical fault in the cylinder 6 injector circuit.
P0207	Air & Fuel Metering	Injector 7 Circuit Electrical fault in the cylinder 7 injector circuit.
P0208	Air & Fuel Metering	Injector 8 Circuit Electrical fault in the cylinder 8 injector circuit.
P0230	Air & Fuel Metering	Fuel Pump Primary Circuit Fault in the fuel pump primary control circuit or driver module. Tuning note: On returnless Ford systems the fuel pump driver module is a common failure point on higher-horsepower builds.
P1131	Air & Fuel Metering	Lack Of HO2S Switch, Sensor Indicates Lean (Bank 1) Ford-specific: the bank 1 upstream sensor is not switching and is stuck lean. Tuning note: Very common on modular Ford V8s. Check for exhaust leaks ahead of the sensor before condemning it.
P1132	Air & Fuel Metering	Lack Of HO2S Switch, Sensor Indicates Rich (Bank 1) Ford-specific: bank 1 upstream sensor is not switching and is stuck rich.
P1151	Air & Fuel Metering	Lack Of HO2S Switch, Sensor Indicates Lean (Bank 2) Ford-specific version of P1131 for bank 2.
P1152	Air & Fuel Metering	Lack Of HO2S Switch, Sensor Indicates Rich (Bank 2) Ford-specific version of P1132 for bank 2.
P144C	Air & Fuel Metering	Evaporative Emission System Purge Vapor Line Restricted Purge vapor flow is restricted between the canister and the intake.
P0300	Misfire & Ignition	Random / Multiple Cylinder Misfire Detected Misfire detected that is not isolated to one cylinder, based on crankshaft speed variation. Tuning note: Confirm with per-cylinder misfire counts in a datalog. A flashing check engine light means active misfire — stop driving before the converters are destroyed.
P0301	Misfire & Ignition	Cylinder 1 Misfire Detected Misfire detected specifically on cylinder 1.
P0302	Misfire & Ignition	Cylinder 2 Misfire Detected Misfire detected specifically on cylinder 2.
P0303	Misfire & Ignition	Cylinder 3 Misfire Detected Misfire detected specifically on cylinder 3.
P0304	Misfire & Ignition	Cylinder 4 Misfire Detected Misfire detected specifically on cylinder 4.
P0305	Misfire & Ignition	Cylinder 5 Misfire Detected Misfire detected specifically on cylinder 5.
P0306	Misfire & Ignition	Cylinder 6 Misfire Detected Misfire detected specifically on cylinder 6.
P0307	Misfire & Ignition	Cylinder 7 Misfire Detected Misfire detected specifically on cylinder 7.
P0308	Misfire & Ignition	Cylinder 8 Misfire Detected Misfire detected specifically on cylinder 8.
P0316	Misfire & Ignition	Misfire Detected On Startup Misfire occurred within the first few seconds after starting.
P0325	Misfire & Ignition	Knock Sensor Circuit (Bank 1) Knock sensor circuit fault on bank 1 — the PCM cannot trust its detonation input. Tuning note: Never add timing with knock detection offline. On a boosted Ford this is how pistons get holed.
P0330	Misfire & Ignition	Knock Sensor Circuit (Bank 2) Knock sensor circuit fault on bank 2.
P0351	Misfire & Ignition	Ignition Coil A Primary / Secondary Circuit Fault detected in the cylinder 1 ignition coil circuit. Tuning note: Coil-on-plug numbering follows cylinder order. Higher cylinder pressure from a tune finds a marginal coil that idled fine before.
P0352	Misfire & Ignition	Ignition Coil B Primary / Secondary Circuit Fault detected in the cylinder 2 ignition coil circuit.
P0353	Misfire & Ignition	Ignition Coil C Primary / Secondary Circuit Fault detected in the cylinder 3 ignition coil circuit.
P0354	Misfire & Ignition	Ignition Coil D Primary / Secondary Circuit Fault detected in the cylinder 4 ignition coil circuit.
P0355	Misfire & Ignition	Ignition Coil E Primary / Secondary Circuit Fault detected in the cylinder 5 ignition coil circuit.
P0356	Misfire & Ignition	Ignition Coil F Primary / Secondary Circuit Fault detected in the cylinder 6 ignition coil circuit.
P0357	Misfire & Ignition	Ignition Coil G Primary / Secondary Circuit Fault detected in the cylinder 7 ignition coil circuit.
P0358	Misfire & Ignition	Ignition Coil H Primary / Secondary Circuit Fault detected in the cylinder 8 ignition coil circuit.
P1000	Misfire & Ignition	OBD Systems Readiness Test Not Complete Ford-specific: the on-board monitors have not finished running since the last code clear. Tuning note: Not a fault. It appears after every tune flash or battery disconnect and clears itself once the drive cycle completes — but it will fail an emissions test until it does.
P1112	Misfire & Ignition	Intake Air Temperature Sensor Intermittent Ford-specific: the IAT signal is dropping in and out.
P000A	Camshaft & VCT	Camshaft Position Slow Response (Bank 1 Intake) The bank 1 intake camshaft is moving to its commanded position too slowly. Tuning note: A known Coyote complaint. Oil quality and phaser condition matter here more than the calibration.
P000B	Camshaft & VCT	Camshaft Position Slow Response (Bank 1 Exhaust) The bank 1 exhaust camshaft responds too slowly to commands.
P0010	Camshaft & VCT	Camshaft Position Actuator Circuit (Bank 1) Electrical fault in the bank 1 variable cam timing solenoid circuit. Tuning note: Coyote and EcoBoost engines depend on VCT for both power and idle quality. A stuck solenoid ruins both.
P0011	Camshaft & VCT	Camshaft Position Over-Advanced (Bank 1) The bank 1 camshaft is more advanced than commanded, or will not return to the commanded position. Tuning note: Frequently oil-related — pressure, viscosity, or a screen full of debris. Cam timing limits in the calibration must match the hardware fitted.
P0012	Camshaft & VCT	Camshaft Position Over-Retarded (Bank 1) The bank 1 intake camshaft is retarded beyond the commanded position.
P0013	Camshaft & VCT	Camshaft Position Actuator Circuit (Bank 1 Exhaust) Electrical fault in the bank 1 exhaust camshaft actuator circuit.
P0014	Camshaft & VCT	Exhaust Camshaft Position Over-Advanced (Bank 1) Bank 1 exhaust cam timing is advanced beyond the commanded value.
P0016	Camshaft & VCT	Crankshaft / Camshaft Position Correlation (Bank 1 Sensor A) Crankshaft and camshaft signals are out of phase beyond tolerance. Tuning note: Worn timing chains and stretched guides are a known weak point on high-mileage modular and EcoBoost engines. Mechanical repair only — never tune around it.
P0017	Camshaft & VCT	Crankshaft / Camshaft Position Correlation (Bank 1 Sensor B) Correlation fault between the crankshaft and bank 1 exhaust camshaft signals.
P0018	Camshaft & VCT	Crankshaft / Camshaft Position Correlation (Bank 2 Sensor A) Correlation fault on bank 2 between crankshaft and intake camshaft.
P0019	Camshaft & VCT	Crankshaft / Camshaft Position Correlation (Bank 2 Sensor B) Correlation fault on bank 2 between crankshaft and exhaust camshaft.
P0020	Camshaft & VCT	Camshaft Position Actuator Circuit (Bank 2) Electrical fault in the bank 2 camshaft actuator solenoid circuit.
P0021	Camshaft & VCT	Camshaft Position Over-Advanced (Bank 2) The bank 2 camshaft is more advanced than commanded.
P0022	Camshaft & VCT	Camshaft Position Over-Retarded (Bank 2) The bank 2 camshaft is retarded beyond the commanded position.
P0024	Camshaft & VCT	Exhaust Camshaft Position Over-Advanced (Bank 2) Bank 2 exhaust cam timing is advanced beyond the commanded value.
P0340	Camshaft & VCT	Camshaft Position Sensor Circuit No usable camshaft position signal is reaching the PCM.
P0341	Camshaft & VCT	Camshaft Position Sensor Performance The camshaft signal pattern is implausible relative to the crankshaft signal.
P0345	Camshaft & VCT	Camshaft Position Sensor A Circuit (Bank 2) Fault in the bank 2 camshaft position sensor circuit.
P0521	Camshaft & VCT	Engine Oil Pressure Sensor Performance Measured oil pressure does not match what the PCM expects for current RPM and temperature. Tuning note: Treat as urgent. VCT phasers are hydraulic, so oil pressure problems show up as cam timing faults before anything else.
P0522	Camshaft & VCT	Engine Oil Pressure Sensor Circuit Low Oil pressure circuit reads low — either genuinely low pressure or a sensor fault. Tuning note: Verify with a mechanical gauge before driving. Not a code to tune out.
P0141	Emissions & EVAP	O2 Sensor Heater Performance (Bank 1 Sensor 2) The downstream oxygen sensor heater circuit is not performing to specification.
P0401	Emissions & EVAP	EGR Flow Insufficient The PCM commanded EGR flow and did not see the expected effect.
P0402	Emissions & EVAP	EGR Flow Excessive More EGR flow than commanded — often a stuck-open valve.
P0411	Emissions & EVAP	Secondary Air Injection System Performance The secondary air system did not deliver expected airflow during the cold-start test.
P0420	Emissions & EVAP	Catalyst System Efficiency Below Threshold (Bank 1) The downstream sensor no longer sees the oxygen-storage behavior a healthy catalyst should produce on bank 1. Tuning note: The most misdiagnosed code on the list. Exhaust leaks, a lazy rear sensor, or a rich condition set it without any converter failure. High-flow cats trip it legitimately.
P0430	Emissions & EVAP	Catalyst System Efficiency Below Threshold (Bank 2) Same catalyst efficiency fault as P0420, on bank 2.
P0442	Emissions & EVAP	EVAP System Small Leak Detected The evaporative system failed its leak test at the small-leak threshold — often the fuel cap.
P0443	Emissions & EVAP	EVAP Purge Control Valve Circuit Electrical fault in the purge valve control circuit.
P0446	Emissions & EVAP	EVAP Vent Control Circuit The vent valve or its circuit is not behaving as expected during EVAP testing.
P0455	Emissions & EVAP	EVAP System Large Leak Detected A large evaporative leak — a missing cap, disconnected hose or cracked line.
P0456	Emissions & EVAP	EVAP System Very Small Leak Detected The tightest EVAP leak threshold was failed. Tuning note: Extremely common on F-150s. Check the cap seal and the canister vent before buying parts.
P1450	Emissions & EVAP	Unable To Bleed Up Fuel Tank Vacuum Ford-specific: the PCM could not relieve fuel tank vacuum during the EVAP test. Tuning note: Often a restricted vent, a blocked canister, or a collapsing fuel filler hose.
P2196	Emissions & EVAP	O2 Sensor Signal Stuck Rich (Bank 1 Sensor 1) The upstream sensor signal is stuck at a rich reading regardless of commanded fuel.
P2197	Emissions & EVAP	O2 Sensor Signal Stuck Lean (Bank 1 Sensor 1) The upstream sensor signal is stuck lean regardless of commanded fuel.
P0121	Throttle & ETC	Throttle Position Sensor Performance Throttle position does not correlate with airflow and manifold pressure. Tuning note: A larger throttle body changes flow per degree of opening. The electronic throttle tables should be updated to match.
P0122	Throttle & ETC	Throttle Position Sensor Circuit Low Throttle position signal voltage below the valid range.
P0123	Throttle & ETC	Throttle Position Sensor Circuit High Throttle position signal voltage above the valid range.
P0506	Throttle & ETC	Idle Speed Lower Than Expected Idle speed is below the commanded value beyond tolerance. Tuning note: A camshaft or a big throttle body changes idle airflow requirements. The idle tables need rescaling.
P0507	Throttle & ETC	Idle Speed Higher Than Expected Idle speed is above the commanded value. Tuning note: An intake leak, a ported throttle body, or idle tables that were never adjusted for new hardware.
P1124	Throttle & ETC	Throttle Position Sensor Out Of Self-Test Range Ford-specific: throttle position was outside the expected window during self-test.
P2104	Throttle & ETC	Throttle Actuator Control System Forced Idle The PCM has forced the engine to idle because it does not trust throttle control.
P2111	Throttle & ETC	Throttle Actuator Control System Stuck Open The throttle blade will not close to the commanded position.
P2135	Throttle & ETC	Throttle Position Sensor A/B Correlation The two throttle position signals disagree beyond tolerance. Tuning note: Puts the truck into reduced power mode. Usually a failing throttle body or a corroded connector.
P0700	Transmission	Transmission Control System (MIL Request) The transmission module has stored its own fault and is requesting the check engine light. Tuning note: P0700 is only a pointer — the real code lives in the TCM and needs a capable scan tool to read.
P0715	Transmission	Input / Turbine Speed Sensor Circuit No valid input or turbine shaft speed signal is reaching the transmission module.
P0717	Transmission	Input / Turbine Speed Sensor No Signal The input speed signal is entirely absent.
P0720	Transmission	Output Speed Sensor Circuit Fault in the output shaft speed sensor circuit.
P0730	Transmission	Incorrect Gear Ratio The ratio between input and output speed does not match any commanded gear. Tuning note: On the 10R80 this points at clutch slip. Torque management can hide it briefly — that is a delay, not a repair.
P0740	Transmission	Torque Converter Clutch Circuit Fault in the torque converter clutch control circuit.
P0741	Transmission	Torque Converter Clutch Stuck Off The converter clutch was commanded to lock and slip continued beyond tolerance. Tuning note: Added torque finds a marginal converter clutch immediately. TCC apply pressure and torque limits are part of any serious 10R80 or 6R80 calibration.
P0750	Transmission	Shift Solenoid A Electrical or performance fault in shift solenoid A.
P0755	Transmission	Shift Solenoid B Electrical or performance fault in shift solenoid B.
P0765	Transmission	Shift Solenoid D Electrical or performance fault in shift solenoid D.
P0776	Transmission	Pressure Control Solenoid B Performance A pressure control solenoid is not producing the commanded pressure.
P07E8	Transmission	Transmission Friction Element A Apply Time Range A clutch pack took longer than allowed to apply. Tuning note: Reset adaptives after a transmission calibration change and let it relearn — stacking new tables on stale adaptives makes shift quality worse.
P0812	Transmission	Reverse Input Circuit Fault in the reverse gear input circuit to the transmission module.
P0868	Transmission	Transmission Fluid Pressure Low Measured line pressure is below the commanded value. Tuning note: A worn pump or an internal leak. Commanding higher pressure on top of a mechanical leak does not save the transmission.
P0960	Transmission	Pressure Control Solenoid A Control Circuit Open Open circuit in the line pressure control solenoid.
P17F0	Transmission	Transmission Clutch Adaptive Learning At Limit Adaptive shift corrections have reached the end of their range.
P0033	Boost & Forced Induction	Turbocharger Bypass Valve Control Circuit Fault in the turbo bypass or recirculation valve control circuit.
P0234	Boost & Forced Induction	Turbocharger / Supercharger Overboost Measured boost exceeded the maximum the calibration allows. Tuning note: Standard after a pulley change or a turbo upgrade with stock boost limits. The overboost threshold must be raised deliberately, with fuel and timing to match.
P0236	Boost & Forced Induction	Turbocharger Boost Sensor A Performance The boost pressure sensor reading does not agree with commanded boost and other engine inputs. Tuning note: EcoBoost calibrations pull timing on charge temperature, so verify intercooler and IAT2 data alongside this code. An upgraded intercooler is often worth more than a more aggressive tune.
P0243	Boost & Forced Induction	Turbocharger Wastegate Solenoid A Fault in the wastegate control solenoid circuit.
P0245	Boost & Forced Induction	Turbocharger Wastegate Solenoid A Low Wastegate solenoid circuit voltage below the valid range.
P0246	Boost & Forced Induction	Turbocharger Wastegate Solenoid A High Wastegate solenoid circuit voltage above the valid range.
P0299	Boost & Forced Induction	Turbocharger / Supercharger Underboost Boost is below the commanded target. Tuning note: The signature EcoBoost complaint. Check charge-pipe couplers, the intercooler and wastegate actuator travel before touching the tune — a boost leak is not a calibration problem.
P02EE	Boost & Forced Induction	Cylinder 1 Injector Circuit Range / Performance Direct injection performance fault on cylinder 1 — commonly flagged on high-output EcoBoost engines. Tuning note: Often surfaces alongside fuel pressure faults when the direct-injection system is at its limit.
P0601	Communication & Module	Internal Control Module Memory Checksum Error The PCM's internal memory failed its checksum test. Tuning note: An interrupted write can cause this. Never flash on a weak battery — use a maintainer.
P0602	Communication & Module	Control Module Programming Error Required calibration data is missing or incomplete. Tuning note: Normal on a replacement module before programming, and after a flash that did not finish.
P0603	Communication & Module	Internal Control Module Keep Alive Memory Error Keep-alive memory was lost or failed its test. Tuning note: Ford relearns fuel trims and idle from KAM. Expect a few hundred miles of adaptation after it is reset.
P0605	Communication & Module	Internal Control Module ROM Error The PCM's read-only memory failed its self-test.
P1260	Communication & Module	Theft Detected — Engine Disabled Ford-specific: the PATS anti-theft system has disabled the engine. Tuning note: Shows up after key, cluster or PCM work. The anti-theft system must be relearned to the vehicle before it will start.
U0100	Communication & Module	Lost Communication With PCM Another module can no longer communicate with the powertrain control module. Tuning note: Appears after an interrupted flash. Recover the module properly rather than disconnecting the battery and hoping.
U0101	Communication & Module	Lost Communication With TCM The transmission control module has stopped responding on the network.
U0140	Communication & Module	Lost Communication With Body Control Module The BCM is not answering network requests.
U0155	Communication & Module	Lost Communication With Instrument Cluster The cluster is not communicating on the network.
U0401	Communication & Module	Invalid Data Received From PCM A module received powertrain data it considers implausible.
P0217	Sensors & Electrical	Engine Over Temperature Condition The PCM recorded coolant temperature above its safe limit. Tuning note: Sustained high coolant temperature is a hardware problem. Raising thresholds in a tune to silence it is how head gaskets fail.
P0335	Sensors & Electrical	Crankshaft Position Sensor Circuit The crankshaft position signal is missing or erratic. Tuning note: An erratic crank signal causes stalling and phantom misfire codes. Check the connector and reluctor wheel.
P0336	Sensors & Electrical	Crankshaft Position Sensor Performance The crankshaft signal is present but its pattern is implausible.
P0480	Sensors & Electrical	Cooling Fan 1 Control Circuit General fault in the primary cooling fan control circuit.
P0500	Sensors & Electrical	Vehicle Speed Sensor No usable vehicle speed signal reaching the PCM. Tuning note: Tire size and axle ratio changes must be entered in the calibration or speed, shift points and the speedometer are all wrong.
P0562	Sensors & Electrical	System Voltage Low Charging system voltage is below the PCM's minimum threshold. Tuning note: Fix charging problems before flashing. Low voltage mid-write is how modules get bricked.
P0563	Sensors & Electrical	System Voltage High System voltage above the expected range — typically overcharging.
P061B	Sensors & Electrical	Internal Control Module Torque Calculation Performance The PCM's torque model does not agree with measured engine behavior. Tuning note: Hardware changes that alter airflow without a matching calibration update will set this on later Ford PCMs.
P0645	Sensors & Electrical	A/C Clutch Relay Control Circuit Fault in the air conditioning clutch relay circuit.
P0691	Sensors & Electrical	Cooling Fan 1 Control Circuit Low The cooling fan control circuit reads low — relay, wiring or motor. Tuning note: Fan-on temperatures are commonly lowered in a performance calibration. Verify the fans actually respond afterward.
P1636	Sensors & Electrical	Inductive Signature Chip Communication Error Ford-specific internal module communication fault.
P2110	Sensors & Electrical	Throttle Actuator Control System Forced Limited RPM The PCM has capped engine speed because it does not trust throttle control.

How to Read the Code Numbers

The first character tells you which system stored the fault. P is powertrain, U is network or communication, B is body, and C is chassis.

The second character tells you who defined it. P0xxx codes are generic and mean the same thing on every OBD-II vehicle sold since 1996. P1xxx codes are manufacturer specific. The P2xxx and P3xxx ranges are a mix of both, and newer modules also use hexadecimal codes such as P06DD and P000A.

The remaining digits identify the specific circuit, cylinder, or monitor. Injector codes P0201 through P0208 and coil codes P0351 through P0358 both follow cylinder order, not firing order — a detail that sends plenty of people chasing the wrong coil.

One more thing worth knowing: a stored code is a symptom report, not a diagnosis. P0420 does not mean “replace the catalytic converter.” It means the downstream oxygen sensor no longer sees the difference it expects to see. An exhaust leak, a lazy sensor, or a fueling problem produce the same code.

Codes We See After a Tune

Some codes are hardware failures. Others are the module correctly reporting that the engine no longer matches the calibration it was given. The second group is fixable in software, and it is the group we deal with every day:

P1000 — not a fault at all. It means the on-board monitors have not finished running since the last flash or battery disconnect. It clears itself after a full drive cycle, but it will fail an emissions test until it does.

P0101 — a cold-air intake with a stock MAF curve. P0128 — a low-temperature thermostat the warm-up thresholds were never adjusted for. P0234 — a pulley or turbo upgrade against a stock overboost limit. P0172 or P0175 — larger injectors with factory slope and offset data. P0140 — rear O2 sensors removed for an off-road pipe without disabling the rear monitors.

And the ones that must never be tuned around: P0016 through P0019 crank-to-cam correlation (timing chains and phasers), P0521 and P0522 oil pressure, P0325 and P0330 knock sensor faults, P0217 overheating, and any misfire under load. P0299 underboost on an EcoBoost is almost always a boost leak — a blown charge-pipe coupler is a hose clamp, not a calibration.

Got a Ford Code You Cannot Solve?

Send us the code and a datalog. We read MAF, knock, fuel trim, boost and misfire data on every remote tune submission and we will tell you straight whether it is a calibration fix or a hardware problem.

Talk to a Tuner

Frequently Asked Questions

How do I read DTC codes on a Ford?

Any generic OBD-II scanner plugged into the port under the dash will read stored P-codes. Ford's own P1xxx codes and module-level faults in the TCM, BCM or ABS need a capable scan tool or tuning software such as HP Tuners to read properly — a cheap reader will show you P0700 and stop there.

Why does P1000 keep coming back after a tune?

P1000 is Ford's readiness code, not a failure. Every time the PCM is flashed or the battery is disconnected the monitors reset and P1000 is stored until a complete drive cycle runs them all. Normal mixed driving over a few days clears it.

Will a custom tune clear my check engine light?

Only when the code came from a calibration limit rather than a mechanical fault. Rescaling a MAF curve for a new intake, adjusting warm-up thresholds for a low-temp thermostat, or raising a stock overboost limit are real fixes. A failed coil, a stretched timing chain or a leaking injector are not, and we will not mask a hardware fault behind a calibration change.

My EcoBoost has P0299 underboost. Is that a tune problem?

Usually not. P0299 means the engine did not make the boost it asked for, and on EcoBoost engines the cause is most often a charge-pipe coupler that popped off, a cracked intercooler, or wastegate actuator travel. Fix the leak first — chasing it in software just hides the symptom.

Does my Ford have cylinder deactivation codes?

Ford's V8s do not use the cylinder-deactivation systems found on GM and HEMI engines, so those code families do not apply. Ford's equivalent complexity is variable cam timing — the P0010 through P0024 and P000A range — which is hydraulic and therefore very sensitive to oil condition and pressure.

Can I keep driving with the check engine light on?

It depends on the code. A very small EVAP leak is not urgent. Crank-to-cam correlation, low oil pressure, overheating, or misfire under load can destroy an engine. If the light is flashing, stop — a flashing MIL means active misfire dumping raw fuel into the catalytic converters.

More Tuning Tips

Ford PCM & TCM Unlocking / Programming · Ford Mustang & F-150 Remote Tuning · MAP Sensor kPa to Boost Conversion Chart · HP Tuners Credit System Explained

Tuning a different platform? See our Dodge, Jeep, RAM & Chrysler DTC code list.

This list is a reference for diagnosis, not a repair manual. Definitions describe what the module detected — always confirm with a proper diagnosis before replacing parts. Coverage focuses on 2005 and newer Ford and Lincoln gasoline platforms, including Coyote, modular, EcoBoost and Godzilla engines.