What is the P0035 Code?
The P0035 diagnostic code is a generic OBD-II code related to the powertrain. It indicates a malfunction in the turbocharger wastegate control circuit. This code applies to a wide range of brands (VW, Dodge, Ford, GM, etc.) manufactured since 1996, but specific repair steps vary significantly from model to model.
Operation and Symptoms of the Fault
When the PCM (Powertrain Control Module) detects an abnormally high voltage or an excessive boost condition in the wastegate circuit, it logs the P0035 code and illuminates the Malfunction Indicator Lamp (Check Engine).
Common Symptoms
- Loss of power and slow acceleration
- Abnormal noises from the turbocharger
- Black smoke from the exhaust
- Abnormal increase in engine temperatures
- Engine knocking and fouled spark plugs
- Other related codes (misfires, knock sensor)
Potential Causes of the P0035 Code
Several failures can cause this code:
- Faulty boost pressure sensor (common cause)
- Failure of the wastegate or its actuator
- Electrical problems (short circuit, open circuit, corroded connectors)
- Damaged vacuum lines (on vacuum-controlled systems)
- PCM or boost controller failure
Diagnosis and Repair Procedures
WARNING: Incorrect boost pressure can cause serious engine damage. It is crucial to have this code checked promptly.
Preliminary Steps
- Consult your manufacturer’s Technical Service Bulletins (TSBs) to identify any known issues.
- Perform a thorough visual inspection: check the condition of cables, connectors, and vacuum hoses.
- Read and record all fault codes and freeze frame data, then attempt a reset.
Technical Approach
The wastegate, whether electronic or vacuum-controlled (via a solenoid), is managed by the PCM to maintain boost pressure within an optimal range (typically between 9 and 14 psi). Accurate diagnosis requires using a scan tool and often the specific vehicle’s repair manual.
Experiencing this issue? Given the complexity of turbo systems, it is highly recommended to entrust the diagnosis and repair to a qualified professional to avoid any collateral damage to the engine.