What does fault code P0029 mean?
The P0029 fault code, applicable to all car manufacturers, means “Exhaust Valve Control Solenoid Circuit Range/Performance (Bank 2)“.
Background Information: The camshaft controls the opening and closing of the valves. In a variable valve timing system, the electronic camshaft adjusting valve (or oil control valve, OCV) adjusts the camshaft angle by changing the oil pressure to the camshaft adjuster (mechanical type) according to instructions from the engine control module (ECM), ensuring the valves open and close at optimal times. This fault code appears if the actual position of the B (exhaust) camshaft differs from the ideal position by more than 20 degrees.
P0029 Error Code Symptoms
- Unstable engine idle
- Loss of power during acceleration
- Increased fuel consumption
- Difficulty starting the engine
- Engine malfunction indicator light illuminated
Main Causes of P0029 Error Code
- Faulty VVT solenoid (Bank 2)
- Damaged or shorted wiring
- VVT system contaminated with oil deposits
- Low or dirty engine oil
- Engine Control Module (ECM) malfunction
P0029 Error Code in Different Vehicles
Audi P0029: In Audi models equipped with TFSI engines, the error may be caused by dirty oil passages or a faulty phase control valve.
BMW P0029: BMWs are characterized by their VVT system being extremely sensitive to oil quality. Contaminated oil often leads to the P0029 error.
Ford P0029: Ford Focus and Fusion vehicles often experience the P0029 error when there are wiring faults or breaks in the VVT circuit.
Mazda P0029: In Mazda 6 and CX-5 models equipped with Skyactiv engines, the fault may be due to a defect in the exhaust valve phase adjustment.
P0029 in Mercedes-Benz: In Mercedes-Benz models, the P0029 error may occur when the oil pressure drops or the engine control unit malfunctions.
How to Diagnose P0029 Error Code?
Step 1: Read the error code with an OBD2 diagnostic scanner
Step 2: Check the condition and level of the engine oil
Step 3: Visually inspect the wiring and valve connectors
Step 4: Check the resistance of the VVT valve with a multimeter
Step 5: Check for contaminants in the oil supply passages to the VVT system
| Possible Causes | How to Check？ |
|---|---|
| Faulty VVT valve | Measure resistance with a multimeter |
| Open or shorted wiring | Visual inspection, tester check |
| Dirty oil | Check oil level and condition |
| Electronic countermeasure failure | Scanner diagnosis, flash/replace |
Tools Needed: OBD2 diagnostic scanner, multimeter, set of wrenches and screwdrivers, gloves and flashlight to inspect the engine compartment
How to Fix P0029 Error Code? (Solutions to the Problem)
Simple Fixes
- Engine oil and oil filter replacement
- Clean VVT solenoid valve connector
- Reset the error using an OBD2 scanner after addressing the cause
In-depth Diagnosis and Repair Solutions
- Replace the defective VVT solenoid valve (Bank 2)
- Repair or replace damaged wiring
- Oil passage flushing
- ECM diagnosis and possible replacement
| Symptoms | Possible Solutions |
|---|---|
| Unstable engine operation | Check and replace the VVT valve |
| Increased fuel consumption | Change engine oil and filter |
| Difficult starting | Check the valve power supply circuit |
P0029 Error FAQ
Is it possible to drive with a P0029 error?
No. A P0029 error can cause unstable engine operation and reduced performance. Prolonged use may lead to more serious damage.
How do I reset the P0029 error code?
The reset can be done with an OBD2 scanner or by disconnecting the battery for 10-15 minutes. However, if the fault persists, the error will reappear.
Does a P0029 error require replacing the VVT valve?
Not necessarily. Sometimes simply changing the oil or cleaning the valve contacts is sufficient. However, if the valve is defective, it will need to be replaced.
Does a P0029 error affect fuel consumption?
Yes, if the valve timing is compromised, the engine’s efficiency decreases, potentially leading to increased fuel consumption.
Can dirty oil cause a P0029 error?
Yes. Contaminated oil can clog the oil passages of the VVT system, interfering with the solenoid valve’s operation and causing the error.
Related OBD2 Errors
P0010 – A Camshaft Position Actuator Circuit/Open (Bank 1)
P0020 – A Camshaft Position Actuator Circuit/Open (Bank 2)
P0028 – Intake Valve Control Solenoid Circuit Range/Performance (Bank 2)
Important! If the P0029 error is accompanied by other fault codes, a comprehensive diagnosis is necessary. Ignoring it may lead to expensive repairs. Monitor oil quality and level, and perform regular engine maintenance. This will help prevent the recurrence of the error and extend the life of the engine.