Fault Code Lookup

Camshaft Position A — Timing Over-Advanced (Bank 1)

The intake camshaft timing on bank 1 is more advanced than the ECM has commanded. This typically indicates a problem with the variable valve timing (VVT) system.

Camshaft Position A — Timing Over-Retarded (Bank 1)

The intake camshaft timing on bank 1 is more retarded than the ECM commanded. This can cause poor idle quality, reduced fuel economy, and increased emissions.

Exhaust Camshaft Position Actuator Circuit (Bank 1)

The ECM has detected a fault in the exhaust camshaft position actuator solenoid circuit on bank 1. This affects variable valve timing on the exhaust side.

Crankshaft/Camshaft Position Correlation (Bank 1 Sensor A)

The crankshaft and camshaft positions are not in the expected alignment. This usually indicates a timing issue that can cause rough running, reduced power, or a no-start condition.

Fuel Pressure Regulator Performance

The fuel pressure is not matching what the ECM has commanded. This can cause hard starting, poor acceleration, stalling, or engine running rough, particularly on common rail diesel systems.

Mass Air Flow (MAF) Sensor Circuit Malfunction

The MAF sensor circuit has a complete failure or is sending no signal. Unlike P0101 (range/performance), this code indicates a total circuit fault — the ECM sees no data at all from the sensor.

Mass Air Flow Sensor Range/Performance

The mass airflow sensor is reading outside its expected range. This can cause poor fuel economy, rough idle, hesitation on acceleration, and black smoke from the exhaust.

MAP/Barometric Pressure Circuit Range/Performance

The manifold absolute pressure sensor is reading outside its expected range for the current engine operating conditions. This affects fuel delivery and ignition timing calculations.

Intake Air Temperature Sensor High Input

The intake air temperature (IAT) sensor is reading an abnormally high temperature. This may indicate a sensor fault or wiring issue, causing the ECM to use incorrect air density calculations.

Engine Coolant Temperature Sensor Circuit

The engine coolant temperature (ECT) sensor circuit is sending a signal outside the expected range. This sensor is critical for fuel mixture, ignition timing, and fan control.

Coolant Thermostat Below Regulating Temperature

The engine is taking too long to reach normal operating temperature. This usually means the thermostat is stuck open, allowing coolant to flow continuously.

O2 Sensor Circuit Low Voltage (Bank 1, Sensor 1)

The upstream oxygen sensor on bank 1 is reporting a consistently low voltage, indicating a lean exhaust condition or a sensor fault. The ECM uses this sensor for fuel trim adjustments.

O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)

The heater element in the upstream O2 sensor on bank 1 has failed or its circuit has a fault. The heater brings the sensor to operating temperature quickly after a cold start.

System Too Lean (Bank 1)

The engine control module has detected that the air-fuel mixture is too lean on bank 1 — meaning there is too much air or not enough fuel entering the combustion chamber.

System Too Rich (Bank 1)

The engine is running rich on bank 1 — too much fuel relative to air is entering the combustion chamber, leading to poor fuel economy and potential catalyst damage.

System Too Lean (Bank 2)

Similar to P0171 but on bank 2. The engine is running lean on the second bank of cylinders, typically found on V6 and V8 engines.

Turbocharger Overboost Condition

The turbocharger is producing more boost pressure than expected. The ECM has detected this and may limit engine power to protect components.

Turbocharger/Supercharger Underboost

The turbocharger or supercharger is not producing the expected amount of boost pressure. This results in noticeable power loss, especially under acceleration.

Random/Multiple Cylinder Misfire Detected

The engine is misfiring across multiple cylinders rather than just one. This can cause rough idling, loss of power, and increased emissions.

Cylinder 1 Misfire Detected

A misfire has been specifically detected in cylinder 1. The ECU has identified that this cylinder is not producing the expected power contribution, causing rough running and potential catalyst damage.

Cylinder 2 Misfire Detected

A misfire has been specifically detected in cylinder 2. This is more targeted than a P0300 random misfire and helps narrow down the fault to components serving that cylinder.

Cylinder 3 Misfire Detected

A misfire has been detected specifically in cylinder 3. This isolates the fault to components serving that particular cylinder, making diagnosis more targeted than a random misfire code.

Cylinder 4 Misfire Detected

Cylinder 4 is misfiring. The crankshaft position sensor has detected a variation in engine speed that isolates the problem to this specific cylinder.

Knock Sensor 1 Circuit Malfunction

The knock sensor is not sending a valid signal to the ECM. This sensor detects engine knock (detonation) so the ECM can retard ignition timing to prevent damage.

Crankshaft Position Sensor A Circuit Malfunction

The ECM is not receiving a reliable signal from the crankshaft position sensor. This sensor is critical for engine timing and fuel injection — without it, the engine may not start.

Camshaft Position Sensor Circuit Malfunction

The engine control module is not receiving a proper signal from the camshaft position sensor. This can cause starting problems, rough running, or engine stalling.

Camshaft Position Sensor A Range/Performance (Bank 1)

The camshaft position sensor signal is present but is outside the expected range or has intermittent dropouts. This can cause rough running, stalling, or no-start conditions.

Ignition Coil B Primary/Secondary Circuit

A fault has been detected in the primary or secondary circuit of ignition coil B (cylinder 2 on most engines). This will typically cause a misfire on the associated cylinder.

Glow Plug/Heater Circuit A Malfunction

A fault has been detected in the glow plug heating circuit. Glow plugs are essential for cold-starting diesel engines — they preheat the combustion chamber to aid ignition.

Exhaust Gas Recirculation (EGR) Flow Malfunction

The EGR system is not functioning as expected. The ECM has detected that the EGR flow does not match what was commanded, either too much or too little recirculation.

Exhaust Gas Recirculation (EGR) Flow Insufficient

The EGR system is not flowing enough exhaust gas back into the intake. This is a common issue on diesel and petrol engines, often caused by carbon buildup.

EGR Control Circuit Range/Performance

The EGR valve position does not match what the ECM has commanded. The valve may be sticking, responding slowly, or the position sensor may be faulty.

Catalyst System Efficiency Below Threshold (Bank 1)

The catalytic converter on bank 1 is not operating efficiently enough. The downstream O2 sensor is showing readings too similar to the upstream sensor.

EVAP Emission Control System Malfunction

A general fault has been detected in the evaporative emission control system. This system captures fuel vapours from the tank and feeds them into the engine to be burned.

EVAP System Small Leak Detected

A small leak has been detected in the evaporative emissions control system. This system prevents fuel vapours from escaping into the atmosphere.

EVAP Vent Control Circuit Malfunction

The EVAP system vent valve or its control circuit has a fault. The vent valve allows fresh air into the charcoal canister during purge cycles and seals the system during leak testing.

EVAP System Large Leak Detected

A large leak has been detected in the evaporative emissions system. This is often simpler to diagnose than a small leak and is frequently caused by a missing or loose fuel cap.

EVAP System Very Small Leak Detected

An extremely small leak has been detected in the EVAP system. These are often the hardest to find and may be intermittent, especially in cold weather when seals contract.

Fuel Level Sensor Circuit High Input

The fuel level sensor is sending a signal that is higher than the expected range. This typically causes an inaccurate fuel gauge reading, often showing full when it is not.

Vehicle Speed Sensor Malfunction

The vehicle speed sensor is sending an incorrect or no signal to the ECM. This can affect speedometer readings, transmission shifting, and cruise control operation.

Brake Switch Correlation

The brake light switch signals are inconsistent. This can prevent cruise control from working and may cause transmission shifting issues or warning lights.

Idle Air Control System RPM Higher Than Expected

The engine idle speed is higher than the ECM expects. The idle control system cannot bring the RPM down to the target, indicating an air leak or control fault.

Engine Oil Pressure Sensor/Switch Circuit

The oil pressure sensor or its circuit is sending readings outside the expected range. This can be a sensor fault or a genuine low oil pressure warning that requires immediate attention.

System Voltage Low

The ECM has detected that the system voltage has dropped below the expected threshold. This can cause various electrical issues and warning lights.

Oil Pressure Control Solenoid Stuck Off

The oil pressure control solenoid is not responding correctly, which can lead to reduced oil pressure and potential engine damage if not addressed.

Transmission Control System Malfunction

The transmission control module has detected a fault and stored a code. P0700 is an informational code that tells you to check the transmission-specific codes for the actual fault.

Diesel Particulate Filter Efficiency Below Threshold

The diesel particulate filter (DPF) is not regenerating properly or has become excessively blocked. This is one of the most common issues on modern diesel vehicles.

System Too Lean at Idle (Bank 1)

The fuel trim correction at idle indicates a lean condition on bank 1. Unlike P0171 which covers all operating conditions, this code specifically triggers only at idle speed.

Turbo/Supercharger Boost System Performance

The actual boost pressure does not match the target boost. This is a broader code than P0299 (underboost) as it covers any deviation from commanded boost, including intermittent faults.

Diesel Particulate Filter — Soot Accumulation

The DPF soot loading has exceeded the threshold where passive regeneration can clear it. Active regeneration is required but may not be completing successfully due to driving conditions or another fault.