P0025: "B" Camshaft Position - Timing Over-Retarded (Bank 2)
P0025 means "B" Camshaft Position - Timing Over-Retarded (Bank 2). The engine computer compares the camshaft position it commands with the position it actually measures. This code means the "B" (exhaust/right/rear) camshaft on bank 2 (the side opposite cylinder 1) is more retarded than commanded compared with the target, or does not respond as expected.
Can I keep driving? Drivable with care. Diagnose soon: performance, economy or other components can be affected.
Common symptoms
- Check engine light on
- Rough idle or stalling
- Rattle from the timing area on start-up
- Hesitation and reduced power
- Worse fuel economy
Possible causes
- Low oil level, old oil or the wrong oil viscosity
- Sticking oil control valve (VVT solenoid) or a clogged oil screen
- Faulty camshaft phaser
- Stretched timing chain, worn guides or a weak tensioner
- Incorrect timing after a repair
How to diagnose P0025
- Check oil level and condition first. Change oil with the grade the manufacturer specifies.
- On a scan tool, compare desired and actual cam angle at idle and at higher RPM.
- Command the oil control valve and watch whether the actual cam angle follows.
- Remove and inspect the oil control valve and its screen for sludge or debris.
- If cam/crank correlation codes are also present, check timing chain stretch and alignment marks.
Oil condition matters more on VVT engines than many owners expect: sludge or the wrong viscosity is one of the most common causes of this code.
What the code means, digit by digit
Generic codes have the same definition on every OBD-II vehicle (petrol cars from model year 1996 in the US, 2001 in the EU; diesels later). Manufacturers can add their own enhanced codes; those are not listed here.
Related codes
- P0024 "B" Camshaft Position - Timing Over-Advanced or System Performance (Bank 2)
- P0022 "A" Camshaft Position - Timing Over-Retarded (Bank 2)
- P0021 "A" Camshaft Position - Timing Over-Advanced or System Performance (Bank 2)
- P0015 "B" Camshaft Position - Timing Over-Retarded (Bank 1)
- P0014 "B" Camshaft Position - Timing Over-Advanced or System Performance (Bank 1)
- P0012 "A" Camshaft Position - Timing Over-Retarded (Bank 1)
- P0011 "A" Camshaft Position - Timing Over-Advanced or System Performance (Bank 1)
General guidance only. Fault codes describe what the engine computer saw, not which part failed: confirm with testing before replacing parts, and follow the vehicle's service information.