"B" Camshaft Position - Timing Over-Advanced or System Performance (Bank 1)

What it means

The exhaust camshaft on bank 1 is not at the position the ECU commanded, or the variable valve timing system is not responding as expected.

Symptoms

• Check engine light on
• Rough idle
• Reduced power and poor fuel economy
• Rattle from the engine on cold start (chain wear)
• Possible stalling

Probable causes

Most likely first

1. 1Low engine oil level or wrong oil viscosity (variable valve timing runs on oil pressure)
2. 2Overdue oil changes causing sludge in the VVT solenoid screen
3. 3Faulty oil control valve (VVT solenoid)
4. 4Worn VVT actuator (cam phaser)
5. 5Stretched timing chain or jumped timing

How to diagnose it

Work through these in order before buying parts

1. 1Record the code and its freeze frame data (speed, load, temperature when it set), then clear it and see if it comes back.
2. 2Check the oil level and condition first. Top up or change to the correct grade, clear the code and retest. This alone fixes many VVT codes.
3. 3Remove and inspect the oil control valve (VVT solenoid) and its filter screen for sludge.
4. 4Using a scan tool, command the cam timing and watch actual versus desired cam angle.
5. 5Check the solenoid resistance and its wiring.
6. 6If everything else checks out, inspect timing chain stretch and the phaser.
7. 7Check for technical service bulletins (TSBs) or software updates for your make and model; some codes have known factory fixes.

Common fixes

• Change the oil and filter with the correct oil grade
• Clean or replace the VVT solenoid (oil control valve)
• Replace the cam phaser
• Replace the timing chain kit if stretched