P0035
Turbo Charger Bypass Valve Control Circuit HighP0035 is a generic OBD-II powertrain diagnostic trouble code: Turbo Charger Bypass Valve Control Circuit High. It is logged by the engine control unit when the powertrain monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.
What P0035 means
P0035 is stored when the powertrain control module (PCM) detects an abnormally high voltage on the control circuit for the turbocharger or supercharger bypass valve — sometimes referred to as the blow-off or recirculation valve. This valve opens under high boost or during throttle lift-off to divert excess compressed air back to the compressor inlet, protecting the turbo from surge and preventing over-boost damage. The PCM commands the valve via a dedicated output driver and monitors the circuit's return signal; a sustained high-voltage reading (typically above the calibrated upper threshold) triggers this code.
The most common root cause is a short to battery voltage somewhere in the wiring harness between the PCM driver and the valve solenoid connector. A failed solenoid with an internally open coil can also force the circuit into a high-impedance state the PCM interprets as high. In some cases the valve's internal piston seizes in the closed position, and the PCM flags a mismatch between commanded and actual valve state. The fault can also originate at the PCM itself if the output driver transistor fails high.
Because this code can produce either over-boost (if the bypass valve stays fully closed) or erratic boost behaviour, the PCM typically activates a reduced-power or limp-home strategy as a precaution. The check engine light illuminates and may flash. The vehicle should be diagnosed promptly to avoid turbo or engine damage from sustained pressure anomalies.
Common causes
Most-frequently reported root causes when P0035 is logged.
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1
Short to battery voltage in the bypass valve solenoid wiring between the PCM and the valve connector.
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2
Faulty bypass valve solenoid with an internally open or shorted coil.
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3
Bypass valve piston seized in the closed position, causing an actuator-versus-command mismatch.
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4
Corroded or backed-out terminals at the solenoid connector creating high-resistance or open conditions.
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5
Failed PCM output driver transistor delivering sustained high voltage to the circuit.
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6
Damaged or chafed wiring harness routed near hot exhaust components creating an intermittent short.
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7
PCM software fault or corrupted calibration requiring reflash (less common; rule out hardware first).
Symptoms drivers notice
How to diagnose P0035
A typical diagnostic flow when this code is present.
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1
Connect an OBD-II scanner, record freeze-frame data, and note any companion boost codes (P0033, P0034, P0234).
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2
Inspect the bypass valve solenoid connector and harness for corrosion, backed-out pins, and chafe points near exhaust.
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3
With key-on engine-off, measure voltage on the solenoid control wire; it should be near 0 V (or reference voltage only when commanded on) — a resting high reading confirms a short to power.
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4
Measure solenoid coil resistance with an ohmmeter; compare against manufacturer specification (typically 10–40 Ω) — open or very low resistance indicates solenoid failure.
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5
Command the solenoid on and off using a bidirectional scanner and verify actuator movement and voltage transitions on the control wire.
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6
If wiring and solenoid test good, inspect the PCM driver output pin for stuck-high voltage, and consult any applicable technical service bulletins (TSBs) before condemning the PCM.
Related powertrain codes
Frequently asked questions
Can I drive with a P0035 code active?
Short distances at moderate speed are generally possible because the PCM enters a protective limp mode, but sustained driving risks over-boost or under-boost damage to the turbo and engine. Diagnosis should be carried out promptly.
Is P0035 the same as P0034 (circuit low)?
No. P0034 means the PCM detected a below-threshold voltage on the bypass valve circuit (typically a short to ground or open driver), while P0035 means the voltage is above threshold (short to power or failed driver high). Both affect the same valve but indicate opposite electrical failures.
Could a faulty boost pressure sensor alone set P0035?
Indirectly, yes — on some platforms the PCM cross-checks measured boost pressure against bypass valve command. A wildly incorrect boost sensor reading can cause the PCM to interpret the valve circuit as misbehaving. Always check boost sensor plausibility data while diagnosing this code.
Does clearing the code fix the problem?
No. Clearing the code removes the stored fault and turns off the MIL, but if the underlying electrical fault — short, failed solenoid, or PCM driver issue — is not repaired, the code will return as soon as the PCM re-runs the circuit monitor, typically within one drive cycle.
Disabling P0035 in software
RaceTune can permanently disable P0035 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.
Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.
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