P0035 — Turbo Charger Bypass Valve Control Circuit High

OBD2 code P0035 flags a problem with the turbocharger / supercharger boost control (turbo charger bypass valve control circuit high). Short, gentle driving to a shop is usually possible. Common culprits: stuck wastegate or faulty boost control solenoid, worn turbocharger, vacuum or actuator line damage.

powertrain (engine/transmission)

Is it safe to drive?

Caution: reduced or unstable boost is possible If engine output and boost remain stable, avoid heavy acceleration and arrange prompt diagnosis. Stop driving if boost becomes erratic, the engine develops a severe misfire, or the vehicle enters a power-limiting condition.

Typical symptoms

The check-engine light illuminates with P0035 stored in the powertrain controller
Turbocharger boost builds more slowly than expected or remains below the intended level
Hesitation, surge, or reduced acceleration occurs when the engine requests boost
Boost gauge readings may be inconsistent with the engine's operating conditions
Some vehicles enter a reduced-power mode when P0035 is active
The engine may run normally until the turbocharger bypass-valve control is requested

Common causes

Open or high-resistance wiring in the P0035 turbocharger bypass-valve control circuit
A short to battery voltage in the bypass-valve solenoid control lead
A failed bypass-valve control solenoid with an internally open or shorted winding
Corroded, heat-damaged, or oil-contaminated electrical connectors
A poor ground or excessive voltage drop in the bypass-valve solenoid ground path
An ECM output-driver failure that leaves the P0035 control circuit reading high

How to diagnose with an OBD scanner

Confirm P0035 and capture operating data Connect an ELM327-based OBD scanner with AIScanAuto, then read stored, pending, and permanent codes. Confirm that P0035 is active and record freeze-frame data such as engine speed, load, boost request, and boost pressure. If supported, compare the commanded bypass-valve state with actual boost response.
Inspect the bypass-valve wiring Examine the harness between the turbocharger bypass-valve solenoid, ECM, and power and ground sources. Look for cracked insulation, chafing, melted terminals, corrosion, water intrusion, or oil contamination. Gently move the wiring and connectors while monitoring the P0035 circuit for an intermittent high reading.
Perform controlled voltage tests With the ignition on, back-probe the control and ground terminals at the bypass-valve connector and ECM. Follow the vehicle wiring diagram because pin assignments vary. A high reading at both the ECM and valve may indicate an open circuit or failed load, while a high reading only at the ECM can indicate a short to power or an ECM driver problem.
Test the solenoid and ground path Disconnect the bypass-valve control solenoid and check its resistance and terminal continuity against the applicable specifications. Measure voltage drop across the ground connection while the circuit is loaded. Confirm the P0035 fault follows the component before replacing it, and do not substitute an unmatched solenoid.
Repair, clear, and verify Repair the damaged wiring, connector, ground, solenoid, or ECM driver as the test results require. Clear P0035 with the scanner, then road-test under light and heavy load while checking for boost, hesitation, and new trouble codes. The code should stay inactive and the bypass valve should respond when boost is requested.

Approximate repair cost

Typical independent-shop estimate: USD $125-$300 for diagnosis, USD $200-$650 for bypass-valve solenoid and wiring or connector repair, and USD $500-$1,200 if the turbocharger bypass-valve or actuator assembly must be replaced. A common total range is USD $250-$1,200. These figures are estimates and vary by region, labor time, and parts availability.

Common questions

What does the High condition mean in P0035?

P0035 means the ECM detected a voltage above its expected range in the turbocharger bypass-valve control circuit. It is primarily an electrical fault involving the solenoid, wiring, connectors, ground, or ECM driver.

Will P0035 always cause the turbocharger not to make boost?

No. P0035 identifies an abnormal high circuit voltage, so boost may occasionally remain normal even with the code stored. A separate boost-performance or boost-pressure code may appear if valve operation or actual boost is also incorrect.

Can I drive the vehicle with P0035 active?

A cautious low-load drive may be possible if boost and engine operation remain stable, but heavy acceleration can expose incorrect valve positioning. Prompt electrical diagnosis is advisable, and unstable boost or severe engine operation warrants stopping the vehicle.

Can an ELM327 or AIScanAuto scan identify the P0035 wiring fault?

An ELM327-based scanner with AIScanAuto can confirm P0035 and show related freeze-frame or live data, but it cannot by itself locate an open wire, short, or bad connector. Back-probing and circuit-specific resistance and voltage tests are still required.

When your check engine light comes on and a scan tool reveals code P0035, the engine control unit has detected that the turbocharger bypass valve control circuit is running at a voltage higher than it should — essentially reading close to battery voltage when it should be somewhere in the middle of its operating range. P0035 falls under the powertrain category, specifically addressing boost control systems found on turbocharged and some supercharged engines.

The bypass valve (sometimes called a diverter or blow-off valve, depending on design) serves a practical purpose: when you lift off the throttle, the pressurized air the turbo has been building has nowhere to go. Without a path to release that pressure, the turbo's compressor can stall or suffer from boost spikes that stress the intake system. The bypass valve vents that pressure back toward the turbo inlet or into the atmosphere, protecting the turbo and maintaining proper boost dynamics. The engine control module monitors the valve's position and operation through an electrical circuit. When something pulls that circuit up to high voltage — either a short to power, a broken ground path, or a failed component internally shorted — the module logs P0035.

One important point: the ECU doesn't set P0035 from a single anomalous reading. The fault must persist under specific operating conditions before the module decides it's a real problem and illuminates the warning light. This is why the freeze frame data stored with the code is so valuable — it captures engine speed, load, temperature, and vehicle speed at the exact moment the fault occurred, giving you a starting point for reproduction during diagnosis.

Common Symptoms of P0035

When P0035 is active, you can expect one or more of the following:

The vehicle enters limp-home mode, limiting power and rpm to protect the engine
Noticeable black smoke from the exhaust under acceleration due to improper air-fuel mixture
Significant reduction in engine power and throttle response
Check Engine Light remains illuminated
Increased oil consumption, sometimes from seal leakage caused by boost system issues
Unusual whistling, hissing, or siren-like noise from the engine bay during operation

What Causes P0035?

The root causes, ordered from most to least common:

Defective turbocharger bypass valve with internal electrical failure pulling the signal high
Open or damaged ground return wire for the bypass valve control circuit
Signal wire shorted directly to battery positive voltage
Boost leak somewhere in the intercooler piping, intake hoses, or connections
Worn or fatigued turbocharger with excessive shaft play or oiling issues
Stuck or seized wastegate, or a faulty boost control solenoid
Malfunctioning boost pressure sensor sending incorrect data to the ECU

How to Diagnose P0035

Follow this structured approach to pinpoint the fault without replacing parts unnecessarily:

Connect an OBD2 scanner, confirm P0035 is stored, and record the freeze frame data. This snapshot tells you the engine conditions — load, rpm, temperature, speed — when the fault first appeared.
Scan for any related trouble codes. Secondary codes often point directly to the underlying problem, whether it's a sensor failure or a mechanical boost leak. Also check for any manufacturer TSBs related to P0035 for your specific make and model.
Perform a visual inspection of the turbo boost control wiring harness and connectors. Look for chafed insulation, corroded terminals, broken wires, or loose connections that could interrupt the signal path.
With the bypass valve disconnected, probe the harness connector for signal voltage. If you still read high voltage with the component unplugged, the wiring itself has a short to power. If the voltage drops to normal range, the valve assembly is the culprit.
Pressure-test the intake system and intercooler piping for leaks. Cracked, disconnected, or improperly clamped hoses are a frequent source of boost-related faults and can trigger P0035 indirectly.
Use a scanner to command the boost control solenoid and verify that the wastegate responds correctly. Lack of movement or erratic behavior points to a mechanical or electrical failure in the control circuit.
Clear P0035 after repairs, then drive the vehicle through a complete drive cycle including the conditions recorded in the freeze frame. Confirm the code does not return.

How to Fix P0035

Address the least expensive and most common failures before assuming the worst:

Replace boost control solenoid or actuator: $200–$600
Repair boost leak in hoses, clamps, or intercooler: $100–$400
Turbocharger replacement (if mechanically failed): $1,200–$3,500

The total cost to resolve P0035 typically falls between $100 and $3,500 depending on which component is at fault. A methodical diagnosis before purchasing parts almost always saves money — the turbocharger itself is rarely the first thing to fail, and many P0035 cases are resolved by fixing a simple boost leak or replacing a single solenoid.

Can You Drive with P0035?

Drive with caution. The vehicle may be down on power or operating in limp mode, and pushing it hard risks overheating the engine or causing further damage to the turbocharger. The bypass valve exists to protect the turbo — when it's not functioning properly, the turbo is exposed to conditions that can lead to costly failure. Limit driving to getting the vehicle to a repair facility and avoid high-boost situations until the fault is resolved.