P0025
B Camshaft Position - Timing Over-Retarded Bank 2.
- Generic
- Powertrain
- Generic code
- Medium severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 0
- AreaFuel and air metering, auxiliary emission controls
- 25
- FaultThe specific fault in that area
What it means
P0025 means the engine control unit has found the intake or primary camshaft on bank 2 is sitting further retarded than it has commanded. It compares the camshaft position sensor signal with the crankshaft position signal and the target set for the variable valve timing system. When the difference stays outside the allowed limit, the code sets and the warning light comes on.
Symptoms
- Engine warning light on
- Rough or unstable idle
- Hesitation or reduced power, especially under load
- Poor fuel economy
- Possible hard starting or stalling
- Rattle or ticking from the timing drive on start-up
Possible causes
- Low, dirty or incorrect grade engine oil, or oil sludge restricting the variable timing actuatorlikely
- Faulty camshaft phaser (actuator) on bank 2 that is sticking or not holding positionlikely
- Faulty or blocked oil control solenoid (valve) for the bank 2 camshaft, including a clogged screenlikely
- Wiring or connector fault in the solenoid or camshaft position sensor circuit, such as chafing, corrosion or high resistancepossible
- Stretched timing chain or belt, worn tensioner or guide, or timing out of alignmentpossible
- Faulty camshaft or crankshaft position sensor, or a damaged reluctor wheel giving a wrong signalpossible
- Engine control unit fault or outdated software where the manufacturer has a known fixrare
How to diagnose
- Read all stored and pending codes and the freeze frame data, noting engine temperature, load and rpm when the fault set, and check for related codes such as P0024, P0021 or P0011.
- Check the engine oil level, condition and grade against the manufacturer specification, and note the service history.
- Visually inspect the wiring and connectors to the bank 2 oil control solenoid and camshaft and crankshaft sensors for damage, oil contamination and corrosion.
- Use a scan tool to view live camshaft position against the commanded value, and operate the solenoid with an actuator test if supported.
- Test the solenoid resistance and its supply, earth and control signals against the specification for that engine.
- Remove and inspect the solenoid and its screen for debris or sludge, and check it moves freely.
- Check the sensor signals with a scope or live data and look at the reluctor wheel for damage.
- Check timing chain stretch and correct valve timing, using the method for that engine, if the oil, solenoid and sensor checks show nothing.
How to fix
- Change the engine oil and filter to the correct grade and specification, and address any sludge or low oil level.
- Clean or replace the bank 2 oil control solenoid and its screen.
- Replace the camshaft phaser if it is faulty or not holding position.
- Repair or replace damaged wiring, connectors or terminals in the solenoid or sensor circuit.
- Replace the worn timing chain, tensioner and guides, or correct the timing, as the engine requires.
- Replace a faulty camshaft or crankshaft position sensor, or update the control unit software only where the manufacturer lists it as a fix.
Can I keep driving?
The car can usually be driven a short way at gentle load, but get it checked soon. Continued driving with poor timing control or low oil pressure can cause further wear or engine damage, so stop if you hear rattling or see an oil pressure warning.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.