fault code guide
P0392: Camshaft Position Sensor 'B' Circuit Low (Bank 2)
The engine computer detects that the exhaust camshaft sensor on the second cylinder bank is sending an abnormally low voltage signal. This can make the car difficult to start, run roughly, or feel down on power.
How it shows up: The engine management light stays lit on the dashboard, and you may notice extended cranking before the engine starts, jerky acceleration, or reduced performance. The specific P0392 fault code can be identified using an OBD scanner plugged into the car's diagnostic port.
Updated 9 November 2026
Can I keep driving?
Service soon
While the car is usually drivable for a short time, the computer cannot accurately time fuel injection or variable valve timing, which risks poor running, increased fuel consumption, or sudden stalling.
What to do right now
- 1Note how the engine behaves when starting and whether the engine management light is steady or flashing.
- 2If the engine light begins flashing or the engine runs very roughly, pull over safely and switch off the ignition.
- 3Drive gently and avoid heavy acceleration, towing, or motorway overtaking until the issue is diagnosed.
- 4Book an appointment with a local garage or plug in an OBD reader to check if any other codes have been logged.
Likely causes
Most likely first.
- Likely
Failed camshaft position sensor
Internal electrical failure or heat degradation inside the Bank 2 exhaust camshaft sensor causes the signal voltage to drop near zero.
- Likely
Damaged or shorted wiring harness
The sensor's signal wire can chafe against the hot engine block or cylinder head, creating a short circuit directly to earth.
- Possible
Corroded or loose electrical plug
Moisture or oil leaking from a valve cover gasket can penetrate the connector, corroding the pins or creating high electrical resistance.
- Rare
Timing chain or tensioner wear
A stretched timing chain or worn guide can cause camshaft misalignment, though this usually sets timing correlation codes alongside circuit faults.
What you can check yourself
Park somewhere safe and level, engine off, before you start.
- 1
Locate Bank 2 and inspect the sensor wiring
With the engine switched off and completely cold, open the bonnet and find the exhaust camshaft sensor on Bank 2. Check the wiring harness for signs of chafing, cracked insulation, or damage from heat and rodents.
- 2
Inspect the sensor electrical connector
Carefully unclip the sensor wiring plug. Look inside for bent pins, green corrosion, or engine oil contamination that could cause an electrical short.
- 3
Check the engine oil level and condition
Pull the oil dipstick, wipe it clean, reinsert it fully, and withdraw it to read the level. Variable valve timing systems and camshafts rely heavily on clean, correct oil levels to operate smoothly.
- 4
Scan for related timing or misfire codes
Connect a diagnostic code reader to the OBD port beneath the dashboard. Check if other codes such as crankshaft faults or misfires are logged alongside P0392, which points to a wider timing issue.
Rough cost to fix
Rough estimateTypical prices in Ireland (€) and the UK (£), from an independent garage up to a main dealer. Labour access drives the bill most: on some V-engines, Bank 2 camshaft sensors sit tucked behind the intake plenum or bulkhead and take significant dismantling to reach.
Camshaft position sensor replacement
- Do it yourself
- €40–130£35–110 in the UK
- At a garage
- €120–260£100–220 in the UK
Sensor wiring harness repair or connector replacement
- Do it yourself
- Garage job
- At a garage
- €110–280£95–240 in the UK
Timing chain and tensioner replacement
- Do it yourself
- Garage job
- At a garage
- €800–2,100£700–1,850 in the UK
When to go to a garage
- The engine management light starts flashing, which indicates a severe misfire that can ruin the catalytic converter.
- The car stalls repeatedly or refuses to start after turning the ignition key.
- Rattling or metallic slapping noises come from the timing cover area when the engine is running.
- A replacement sensor does not clear the code, indicating an underlying wiring fault or internal timing problem.
Questions drivers ask
Can I keep driving my car with code P0392?
You can usually drive a short distance to get home or reach a local garage, provided the engine runs smoothly and the engine light is steady. However, the engine management system will revert to backup timing maps, which causes sluggish acceleration, poor fuel economy, and potential sudden cut-outs at junctions. If the light flashes or the engine hesitates heavily, stop driving immediately.
What is the difference between Bank 1 and Bank 2 on an engine?
Bank 1 is the cylinder bank that contains cylinder number one, while Bank 2 refers to the opposite cylinder bank on V6, V8, or horizontally opposed boxer engines. Inline four-cylinder engines do not have a Bank 2, so this code only appears on multi-bank engine layouts. Sensor 'B' specifically refers to the exhaust camshaft sensor rather than the intake sensor.
Will clearing the fault code with an OBD scanner fix the problem?
Clearing the code turns off the dashboard light temporarily, but it will return within one or two drive cycles if the underlying sensor or wiring fault persists. The engine computer runs continuous circuit checks, so a low-voltage signal will immediately re-trigger the fault. A permanent repair requires inspecting the wiring and fitting a replacement sensor.
Will fault code P0392 cause my car to fail the NCT or MOT?
For UK drivers, an illuminated engine management light is an automatic MOT failure on petrol cars registered from July 2003 and diesels from July 2008. In Ireland, the NCT tester will record an engine code as an Advisory Pass on its own, but the car will fail if poor engine timing causes exhaust emissions to exceed legal testing limits. It is always best practice to repair the fault before presenting the vehicle for testing.
Test rules here are for the National Car Test in Ireland (NCT) and the MOT in the UK. Elsewhere, check the regulations of your own country or state before going for a vehicle test.
The warning light you may see
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General guidance for most cars, not a diagnosis of yours. Details differ by make, model and year - check your handbook, and if in doubt, don't drive.