Ford diagnostic trouble codes: common errors with decodings and solutions

BySerge Barrett

Ford vehicles, known for their durability, can still trigger diagnostic trouble codes (DTCs) via the OBD-II system, signaling issues from minor sensor glitches to major mechanical faults. These codes help diagnose problems efficiently, reducing repair time and costs. This guide covers over 80 prevalent codes in Ford models like F-150, Focus, Explorer, and Mustang, categorized by system. Each includes a description, potential causes, and step-by-step solutions based on standard troubleshooting. Always use a scan tool to confirm codes, and consult a professional for complex repairs. Note that while many are generic, some are Ford-specific.

Engine system codes

Engine codes often involve misfires, timing, or coolant issues, leading to rough running or reduced power. These are frequent in high-mileage Fords.

  • P0300: Random/Multiple Cylinder Misfire Detected. Causes: worn spark plugs. Solutions: Swap coils to isolate; replace plugs every 100k miles.
  • P0301: Cylinder 1 Misfire Detected. Causes: issues with plug, wire, and injector. Solutions: Check plug, wire, and injector.
  • P0302: Cylinder 2 Misfire Detected. Causes: issues with plug, wire, and injector. Solutions: Check plug, wire, and injector.
  • P0303: Cylinder 3 Misfire Detected. Causes: issues with plug, wire, and injector. Solutions: Check plug, wire, and injector.
  • P0304: Cylinder 4 Misfire Detected. Causes: issues with plug, wire, and injector. Solutions: Check plug, wire, and injector.
  • P0305: Cylinder 5 Misfire Detected. Causes: issues with plug, wire, and injector. Solutions: Check plug, wire, and injector.
  • P0306: Cylinder 6 Misfire Detected. Causes: issues with plug, wire, and injector. Solutions: Check plug, wire, and injector.
  • P0307: Cylinder 7 Misfire Detected. Causes: issues with plug, wire, and injector. Solutions: Check plug, wire, and injector.
  • P0308: Cylinder 8 Misfire Detected. Causes: issues with plug, wire, and injector. Solutions: Check plug, wire, and injector.
  • P0316: Misfire Detected on Startup (First 1000 Revolutions). Causes: cold start issues. Solutions: Test battery and starter.
  • P0351: Ignition Coil A Primary/Secondary Circuit Malfunction. Causes: faulty coil pack. Solutions: Resistance test and replace.
  • P0352: Ignition Coil B Primary/Secondary Circuit. Causes: faulty coil pack. Solutions: Resistance test and replace.
  • P0353: Ignition Coil C. Causes: faulty coil pack. Solutions: Resistance test and replace.
  • P0354: Ignition Coil D. Causes: faulty coil pack. Solutions: Resistance test and replace.
  • P0355: Ignition Coil E. Causes: faulty coil pack. Solutions: Resistance test and replace.
  • P0356: Ignition Coil F. Causes: faulty coil pack. Solutions: Resistance test and replace.
  • P0115: Engine Coolant Temperature Circuit Malfunction. Causes: thermostat stuck. Solutions: Test coolant flow.
  • P1299: Cylinder Head Overtemperature Protection Active. Causes: overheating. Solutions: Stop and cool engine; check coolant levels.
  • P1289: Cylinder Head Temperature Sensor Circuit High Input. Causes: overheating sensor. Solutions: Verify coolant levels.

Fuel system codes

Fuel-related codes typically signal mixture imbalances or delivery problems, causing poor economy or hesitation.

  • P0001: Fuel Volume Regulator Control Circuit/Open. Causes: wiring faults or a failed solenoid. Solutions: Inspect harness for damage, test solenoid resistance, and replace if needed.
  • P0002: Fuel Volume Regulator Control Circuit Range/Performance. Causes: vacuum leaks or contaminated fuel. Solutions: Check for vacuum leaks or contaminated fuel; clean connections and recalibrate if possible.
  • P0003: Fuel Volume Regulator Control Circuit Low. Causes: short to ground. Solutions: Trace wiring and use a multimeter to verify.
  • P0004: Fuel Volume Regulator Control Circuit High. Causes: short to power. Solutions: Disconnect battery, inspect fuses, and repair shorts.
  • P0087: Fuel Rail/System Pressure Too Low. Causes: clogged fuel filter or weak pump. Solutions: Replace filter and test pump pressure.
  • P0088: Fuel Rail/System Pressure Too High. Causes: stuck regulator. Solutions: Bleed the system and inspect for restrictions.
  • P0171: System Too Lean (Bank 1). Causes: vacuum leaks or faulty oxygen sensor. Solutions: Use smoke test for leaks and replace O2 sensor if readings are off.
  • P0172: System Too Rich (Bank 1). Causes: clogged injectors or bad fuel pressure. Solutions: Clean injectors ultrasonically.
  • P0174: System Too Lean (Bank 2). Causes: vacuum leaks or faulty oxygen sensor. Solutions: Use smoke test for leaks and replace O2 sensor if readings are off.
  • P0175: System Too Rich (Bank 2). Causes: clogged injectors or bad fuel pressure. Solutions: Clean injectors ultrasonically.
  • P1233: Fuel Pump Driver Module Offline. Causes: module failure. Solutions: Replace module.

Transmission system codes

Transmission codes point to shifting or sensor faults, often resulting in limp mode or erratic gears in Ford automatics.

  • P0700: Transmission Control System Malfunction. Causes: TCM issue. Solutions: Scan for sub-codes.
  • P0705: Transmission Range Sensor Circuit Malfunction (PRNDL Input). Causes: faulty neutral safety switch. Solutions: Replace neutral safety switch.
  • P0715: Input/Turbine Speed Sensor Circuit Malfunction. Causes: sensor debris. Solutions: Clean or replace.
  • P0720: Output Speed Sensor Circuit Malfunction. Causes: sensor debris. Solutions: Clean or replace.
  • P0730: Incorrect Gear Ratio. Causes: slipping clutches. Solutions: Fluid change first.
  • P0740: Torque Converter Clutch Circuit Malfunction. Causes: solenoid failure. Solutions: Test pressure.
  • P0750: Shift Solenoid A Malfunction. Causes: solenoid failure. Solutions: Test pressure.
  • P0755: Shift Solenoid B Malfunction. Causes: solenoid failure. Solutions: Test pressure.
  • P0760: Shift Solenoid C Malfunction. Causes: solenoid failure. Solutions: Test pressure.

Emissions and EGR system codes

Emissions codes are common due to strict standards, often from EVAP leaks or catalytic issues, triggering check engine lights.

  • P0400: Exhaust Gas Recirculation Flow Malfunction. Causes: clogged EGR valve. Solutions: Clean or replace valve and passages.
  • P0401: EGR Flow Insufficient Detected. Causes: vacuum hose leak. Solutions: Inspect and seal.
  • P0402: EGR Flow Excessive Detected. Causes: stuck valve. Solutions: Disassemble and lubricate.
  • P0420: Catalyst System Efficiency Below Threshold (Bank 1). Causes: worn catalytic converter. Solutions: Monitor O2 sensors pre- and post-cat.
  • P0430: Catalyst System Efficiency Below Threshold (Bank 2). Causes: worn catalytic converter. Solutions: Monitor O2 sensors pre- and post-cat.
  • P0440: Evaporative Emission Control System Malfunction. Causes: loose gas cap. Solutions: Tighten and reset.
  • P0441: EVAP Incorrect Purge Flow. Causes: faulty purge valve. Solutions: Test solenoid operation.
  • P0442: EVAP Small Leak Detected. Causes: cracked hose. Solutions: Use smoke machine to find.
  • P0443: EVAP Purge Control Valve Circuit Malfunction. Causes: wiring fault. Solutions: Check continuity.
  • P0455: EVAP Large Leak Detected. Causes: damaged filler neck. Solutions: Inspect visually.
  • P0456: EVAP Very Small Leak Detected. Causes: o-ring failure. Solutions: Inspect visually.
  • P1400: DPFE Circuit Low Input. Causes: EGR feedback sensor. Solutions: Clean or replace.
  • P1401: DPFE Circuit High Input. Causes: EGR feedback sensor. Solutions: Clean or replace.
  • P1450: Unable to Bleed Up Fuel Tank Vacuum. Causes: EVAP canister vent solenoid stuck. Solutions: Replace solenoid.

Sensor and electrical system codes

Sensor codes arise from faulty monitoring components, causing inaccurate readings and drivability problems.

  • P0100: Mass or Volume Air Flow Circuit Malfunction. Causes: dirty MAF sensor. Solutions: Clean with MAF cleaner spray and check for intake leaks.
  • P0101: Mass or Volume Air Flow Circuit Range/Performance Problem. Causes: sensor out of spec. Solutions: Calibrate or replace after verifying air filter condition.
  • P0102: Mass or Volume Air Flow Circuit Low Input. Causes: wiring issue or failed sensor. Solutions: Test voltage at sensor pins.
  • P0103: Mass or Volume Air Flow Circuit High Input. Causes: short in wiring. Solutions: Isolate and repair.
  • P0110: Intake Air Temperature Circuit Malfunction. Causes: bad IAT sensor. Solutions: Replace and clear code.
  • P0120: Throttle/Pedal Position Sensor/Switch A Circuit Malfunction. Causes: dirty throttle body. Solutions: Clean and recalibrate.
  • P0121: Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance. Causes: dirty throttle body. Solutions: Clean and recalibrate.
  • P0122: Throttle/Pedal Position Sensor/Switch A Circuit Low Input. Causes: dirty throttle body. Solutions: Clean and recalibrate.
  • P0123: Throttle/Pedal Position Sensor/Switch A Circuit High Input. Causes: dirty throttle body. Solutions: Clean and recalibrate.
  • P0130: O2 Sensor Circuit Malfunction (Bank 1 Sensor 1). Causes: upstream sensor failure. Solutions: Replace with OEM for accuracy.
  • P0131: O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1). Causes: upstream sensor failure. Solutions: Replace with OEM for accuracy.
  • P0132: O2 Sensor Circuit High Voltage (Bank 1 Sensor 1). Causes: upstream sensor failure. Solutions: Replace with OEM for accuracy.
  • P0133: O2 Sensor Circuit Slow Response (Bank 1 Sensor 1). Causes: upstream sensor failure. Solutions: Replace with OEM for accuracy.
  • P0134: O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1). Causes: upstream sensor failure. Solutions: Replace with OEM for accuracy.
  • P0135: O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1). Causes: heater element burned out. Solutions: Replace with OEM for accuracy.
  • P0141: O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2). Causes: heater element burned out. Solutions: Replace with OEM for accuracy.
  • P0150: O2 Sensor Circuit Malfunction (Bank 2 Sensor 1). Causes: upstream sensor failure. Solutions: Replace with OEM for accuracy.
  • P0155: O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1). Causes: heater element burned out. Solutions: Replace with OEM for accuracy.
  • P1504: Idle Air Control Circuit Malfunction. Causes: IAC valve dirty. Solutions: Clean ports.
  • P1506: Idle Air Control Overspeed Error. Causes: IAC valve dirty. Solutions: Clean ports.

Other system codes

These include Ford-specific, chassis, or miscellaneous faults affecting security, readiness, or auxiliary systems.

  • P1000: OBD Systems Readiness Test Not Complete. Causes: appears after battery disconnect. Solutions: Drive cycles to clear.
  • P1131: Lack of HO2S11 Switches – Sensor Indicates Lean. Causes: upstream O2 stuck lean. Solutions: Check for exhaust leaks.
  • P1132: Lack of HO2S11 Switches – Sensor Indicates Rich. Causes: upstream O2 stuck rich. Solutions: Check for exhaust leaks.
  • P1151: Lack of HO2S21 Switches – Sensor Indicates Lean. Causes: upstream O2 stuck lean. Solutions: Check for exhaust leaks.
  • P1260: Theft Detected – Vehicle Immobilized. Causes: PATS system issue. Solutions: Reprogram key.
  • P1633: Keep Alive Power Voltage Too Low. Causes: battery drain. Solutions: Check alternator.
  • P0113: Intake Air Temperature Circuit High Input. Causes: damaged sensor or wiring. Solutions: Inspect wiring; replace sensor.
  • P0128: Coolant Thermostat (Coolant Temp Below Thermostat Regulating Temperature). Causes: faulty thermostat. Solutions: Replace thermostat and coolant.
  • P0500: Vehicle Speed Sensor Malfunction. Causes: faulty speed sensor. Solutions: Inspect wiring and replace sensor.
  • P0603: Internal Control Module Keep Alive Memory (KAM) Error. Causes: battery disconnection. Solutions: Reset and drive to relearn.
  • P0704: Clutch Switch Input Circuit Malfunction. Causes: faulty switch. Solutions: Replace clutch pedal switch.
  • P1001: KOER self test not able to complete. Causes: interrupted test. Solutions: Retry diagnostic procedure.
  • P1100: MAF sensor intermittent. Causes: loose connection. Solutions: Secure wiring and clean sensor.
  • P1101: MAF sensor out of self test range. Causes: contaminated sensor. Solutions: Clean MAF with specialized spray.
  • P1111: System pass. Causes: No fault (informational). Solutions: No action needed.
  • P1112: IAT sensor intermittent. Causes: wiring issue. Solutions: Check harness for damage.

Ford DTCs provide valuable insights into vehicle health, enabling proactive maintenance. Regular scans and addressing codes promptly can extend your Ford’s lifespan and performance. For persistent issues, visit a certified mechanic.

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