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P0029

Exhaust Valve Control Solenoid Circuit Range/Performance Bank 2.

  • Generic
  • Powertrain
  • Generic code
  • Medium severity

How this code is built

P
SystemPowertrain
0
Defined bySAE, the same on every car
0
AreaFuel and air metering, auxiliary emission controls
29
FaultThe specific fault in that area

What it means

P0029 is the generic code for an exhaust valve control solenoid circuit range or performance fault on Bank 2. The engine control unit commands the exhaust camshaft actuator (variable valve timing) and sees the actual cam position fail to follow the target within an acceptable range. The code points to a performance problem with the exhaust valve timing control system, not necessarily an electrical fault in the solenoid itself.

Symptoms

  • Engine warning light on
  • Rough or unstable idle
  • Hesitation or reduced power under acceleration
  • Poor fuel economy
  • Rattling or ticking from the cam drive area on start-up
  • Engine may run in a reduced-performance mode

Possible causes

  • Low, dirty or incorrect grade engine oil, or overdue oil change, affecting the variable timing actuatorlikely
  • Sticking or clogged exhaust valve control (oil control) solenoid or its filter screenlikely
  • Wiring or connector fault at the solenoid, such as chafing, corrosion or high resistancepossible
  • Worn or sticking camshaft phaser/actuator on the Bank 2 exhaust campossible
  • Stretched timing chain or belt, or incorrect cam timing, giving a cam-to-crank correlation errorpossible
  • Faulty camshaft position sensor or damaged reluctor wheel giving a wrong position signalrare
  • Outdated engine control unit software where the manufacturer has issued a calibration fix for this faultrare

How to diagnose

  1. Read all stored and pending codes and the freeze frame data, noting engine temperature, load and rpm when the fault set, and check for related cam timing or misfire codes.
  2. Check the oil level and condition, and confirm the oil grade and service history match the manufacturer specification.
  3. Inspect the Bank 2 exhaust solenoid wiring and connector for damage, oil contamination, corrosion and poor pin tension.
  4. Check the solenoid's resistance and supply and ground against the manufacturer's data, as values vary by engine.
  5. Command the solenoid with a suitable scan tool and compare actual and target exhaust cam angle live data for response and range.
  6. Remove the solenoid and inspect it and its screen for debris, sludge or sticking, and check that it moves freely.
  7. Check cam timing correlation and timing chain stretch, using the procedure for the specific engine.
  8. Check for applicable software updates or technical service bulletins for the model and engine.

How to fix

  • Change the oil and filter to the correct specification and rectify any low oil level or sludge problem.
  • Clean or replace the faulty exhaust valve control solenoid and its screen.
  • Repair or replace damaged wiring, terminals or connectors.
  • Replace the worn camshaft phaser or actuator if testing shows it is not responding.
  • Repair the timing chain, tensioner or guides, or reset the cam timing correctly if it is out.
  • Update the engine control unit calibration only where the manufacturer lists it as a fix for this fault.

Can I keep driving?

Medium severity

Short, gentle journeys are usually possible, but get it checked soon as poor oil flow or timing faults can cause further wear. Stop driving if you hear rattling from the engine, the oil pressure warning lights up or the engine runs very roughly.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.

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