P000B
PowertrainB Camshaft Position Slow Response Bank 1
The exhaust camshaft on bank 2 is moving too slowly when the variable valve timing system tries to swing it to a new position. The ECU expects the cam to hit its target angle within a set time, and when it lags behind that window the code lands. For you that usually shows up as a rough idle, a flat spot on acceleration, and sometimes a brief rattle on cold start. Note the bank 2 part: that's the side of a V engine furthest from cylinder number one, so this only appears on V6s, V8s and a handful of V-layout fours.
ⓘ Information only. This page provides general educational information about fault code P000B. We do not assess the urgency or safety implications of any specific fault. That requires in-person diagnosis by a qualified mechanic. Full terms.
Recommended next steps
Whether a fault is urgent, drivable, or routine depends entirely on the cause on a specific vehicle, and that can only be determined by a qualified mechanic with diagnostic equipment. If a warning light is illuminated, the most reliable next step is professional diagnosis.
What does P000B mean?
P000B is a Powertrain (engine, transmission, fuel system) fault code. It indicates: B Camshaft Position Slow Response Bank 1.
This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms commonly associated with this code
Symptoms that drivers often report alongside this code. Not all may apply to every case:
- • Engine warning light on the dash, often with no other obvious clue at first
- • Lumpy or uneven idle once the engine is up to temperature
- • Hesitation or a flat spot when you accelerate, especially pulling away
- • A short rattle or tick from the cam timing area on cold start
- • Fuel economy creeping up without you changing how you drive
- • Occasional stumble or misfire at low revs in traffic
Possible causes
Causes commonly associated with P000B, listed in approximate order of typical investigation. The actual cause on a specific vehicle can only be confirmed by professional diagnosis.
- 1. Old, sludged, or wrong-grade oil starving the bank 2 cam phaser of pressure. This is the first thing to rule out, and the cheapest. VVT systems are fussy about clean oil at the right viscosity
- 2. Sticking or failed oil control solenoid (the VVT solenoid) on bank 2, either electrically dead or gummed up with varnish so it won't pass oil cleanly
- 3. Worn or seized camshaft phaser on the exhaust cam, the unit that physically rotates the cam relative to the chain
- 4. Camshaft position sensor on bank 2 reading slow or dropping out intermittently, which makes the ECU think the cam is lagging when it isn't
- 5. Damaged wiring or a corroded connector at the solenoid or sensor, common on cars that have had the front end apart
- 6. Stretched timing chain or worn guides on bank 2 throwing the cam timing out of phase. More likely on higher-mileage units
- 7. Blocked oil galleries in the head feeding the phaser, often the end result of years of skipped oil changes
How mechanics typically diagnose
A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training.
- 1. Check the oil level and condition before anything else. If it's low, black, or overdue, change it with the exact grade the handbook specifies and see if the code clears. A lot of P000B faults stop here
- 2. Pull all stored codes. P000B rarely turns up alone, and a partner code like P0021 or a misfire on the same bank tells you a lot about where to look
- 3. Watch live data and compare commanded cam angle against actual cam angle on bank 2 while the engine runs. A cam that won't track the target, or tracks it slowly, confirms the fault is real and not a sensor glitch
- 4. Inspect the bank 2 VVT solenoid and cam sensor wiring and connectors for chafing, corrosion, and loose pins
- 5. Test the bank 2 oil control solenoid: check its resistance against spec and command it open and shut with the scan tool to confirm it actually moves oil
- 6. If the solenoid, sensor, oil and wiring all check out, you're looking at the phaser or chain. That means coming in for a proper inspection, usually with covers off
Common questions about P000B
What am I likely to pay to sort this out? +
Depends entirely which cause it is. If it's just dirty oil, an oil and filter change at an independent runs roughly £60 to £120 and might be the whole job. A bank 2 VVT solenoid is usually a low-three-figure repair, say £120 to £300 fitted at a good independent. Bank 2 access on a V engine is often the awkward back bank, so labour can be higher than you'd expect for a small part. A worn phaser or timing chain is the expensive one, easily £600 to four figures at an independent and more at a main dealer because the front of the engine has to come apart. Get two or three quotes before you commit to chain work.
How do I tell which of these it actually is on my car? +
Work from cheap to expensive. Sort the oil first, because if that fixes it you've saved yourself a fortune. If the code returns, the scan tool live data is the decider: command the cam through its range and watch whether bank 2 actually moves. No movement points at the solenoid or phaser, and you separate those by bench-testing the solenoid. If the solenoid passes and the cam still won't shift, the phaser or the chain is your answer. A rattle on cold start that fades after a few seconds leans towards a worn chain or tensioner rather than a solenoid.
Can I clean the solenoid or do this myself instead of paying a garage? +
You can absolutely try the oil change and a connector clean-up yourself, and pulling the bank 2 solenoid for a soak in carb cleaner is doable if you can reach it. Plenty of stuck solenoids free up once the varnish is washed out. Just note the bank 2 unit is often the harder one to get at on a V engine, sometimes behind the intake. Phaser and chain work is not a driveway job for most people: timing has to be set precisely or you risk bending valves, so that part is best handed over.
If I just clear the code, will it stay gone? +
Only if you fixed what caused it. Clear it on a car with clean oil and a healthy system and it should stay off. Clear it with a sticking solenoid or a stretched chain still in place and it'll come straight back, usually within a few warm-up cycles or as soon as the VVT tries to move under load. Clearing the code is a way to confirm a repair worked, not a fix in itself.
Information only, not professional advice
The information on this page is provided for general guidance and educational purposes only. It is not a substitute for diagnosis or repair advice from a qualified mechanic. Always verify any fault before paying for repairs. carfaultcodes.co.uk accepts no liability for decisions made based on this information. Full terms →