What it means
The ECU detects that the exhaust camshaft oil control valve on bank 2 does not respond to commanded duty cycle within expected limits. Camshaft phase deviates from target during phaser actuation tests.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The Bank 2 exhaust valve control solenoid directs oil to the exhaust cam phaser to adjust exhaust timing. P0029 is set when the module detects that Bank 2 exhaust cam timing does not respond within the expected range to the requested adjustment.
Common causes
Most likely first.
- Oil control valve clogged with sludge
- Low oil pressure or wrong oil viscosity
- Camshaft phaser worn
Symptoms
- Check engine light on
- Rough idle or engine hesitation
- Reduced power or acceleration
- Poor fuel economy
How to diagnose it
- Capture freeze-frame data and compare requested and actual Bank 2 exhaust cam timing in live data to confirm the performance deviation.
- Check the engine oil level, condition, and viscosity against the specified requirements because the exhaust phaser depends on adequate oil flow.
- Inspect the Bank 2 exhaust control solenoid, connector, and wiring for sludge, loose or corroded terminals, and physical damage.
- Test solenoid operation and its control circuit against the wiring diagram and manufacturer’s specification.
- If those checks pass, inspect for restricted oil passages or a sticking or worn Bank 2 exhaust cam phaser.
Common fixes
- Correct low oil level or replace unsuitable or degraded oil and filter with the specified grade.
- Clean the Bank 2 exhaust oil control solenoid and accessible passages if the manufacturer’s procedure allows.
- Repair a loose, corroded, or damaged Bank 2 exhaust solenoid connector or wiring.
- Replace a faulty solenoid or worn exhaust cam phaser when testing confirms the cause.
Can I keep driving?
If the engine runs smoothly and the light stays steady, drive gently and only as needed; exhaust timing problems can cause hesitation, reduced power, and worsening fuel economy. Stop if the engine stalls, runs very roughly, or develops abnormal mechanical noise.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.