Powertrain, generic · Fuel and air metering, auxiliary emission controls

P0029 Exhaust Valve Control Solenoid Circuit Range/Performance (Bank 2)

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

A solenoid valve routes engine oil to a valve control element on the exhaust side of bank 2. Depending on the manufacturer this is a valve lift changeover or a camshaft phaser. P0029 is a plausibility fault: the electrical control is in order, but the expected effect does not occur or comes too late. The control module recognises this from feedback such as an oil pressure switch or the camshaft sensor. Pure circuit faults of the same solenoid have their own codes. The engine usually remains drivable, but with less power and higher consumption. Bank 2 exists only on V and boxer engines.

Likely causes

Oil level too low, wrong viscosity or sludged oil
Feedback oil pressure switch faulty or leaking (systems with switch)
Screen in front of the solenoid clogged, or solenoid sticking
Mechanical fault in the valve train, e.g. locking pin or phaser sticking
Contact resistance in wiring or connector

Symptoms

  • Check engine light on
  • Loss of power, no extra pull at higher engine speed
  • Higher fuel consumption
  • Rough idle possible if a phaser is affected

Repair estimate

DifficultyMediumDIY possible
Parts and labour€50–2,500
Time0–12 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

valve control solenoid exhaust bank2engine oiloil pressure switchvalve train

Related codes

P0027P0028P0084P0085P0086

References: law.cornell.edu, en.wikipedia.org, patents.google.com, ricksfreeautorepairadvice.com.