P0034 Code- Turbocharger Bypass Valve Control Circuit Low

What Does Code P0034 Mean

Note that each manufacturer has a slightly different definition for this code as it is relative to their particular system. This usually means there is a problem with the bypass system for the turbocharger or supercharger to relieve intake air pressure, either completely or partially, depending on how the system is designed.

For this P0035 code, the boost pressure is too low for proper engine operation and power.

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Possible symptoms

• Engine Light ON (or Service Engine Soon Warning Light)

What causes the P0034 code?

A variety of things can cause the Check Engine Light to come on and an OBD-II scanner to indicate this P0034 code.

• Sensor input voltage signals to the engine control module (ECM) that there is an indication of a boost level that is lower than 9 psi or as specified by the manufacturer which will cause a code to be stored and an Check Engine Light lamp to be illuminated. The ECM recognizes the data as an out of specification signal and prevents the ECM to properly control boost levels.
• If the boost is less than 9 psi, it can indicate that pressure is not enough and the system possible has an intake air leak which prevents proper operation and power.
• The turbo charger bypass valve be partially or completely open preventing any boost.
• Intake air hoses, pipes, intercooler or clamps may be defective, damaged, or loose.

Troubleshooting P0034

DTC P0034 will set anytime the engine is running under normal operating conditions and the solenoid position and the commanded position do not match for a set period of time per the manufacturer.

Test the Boost Solenoid

Because of its simplistic design, the first step in diagnosing code P0034 is to check the boost valve itself. Disconnect the boost solenoid and remove it from the vehicle. On the intake end of the valve, blow air orally through the boost solenoid. At rest, the solenoid should allow air to pass through like a straw. If air does not pass through the boost solenoid may be blocked or stuck and should be replaced.

Test the solenoid actuation with a battery source. Attach a positive 12-volt source to the positive terminal of the solenoid, then attach a ground to the negative terminal on the solenoid. The solenoid will click audibly, indicating that the solenoid has switched. Disconnect and reattach the power source multiple times to ensure the solenoid switches consistently. While the wires are connected to the solenoid and it is in the switched position, blow through the solenoid again. Air should not be able to pass through. If air passes through, replace the boost solenoid.

Check the Boost Solenoid Wiring

Any issue with the wiring to the boost solenoid will cause code P0034 to set. Whether there is high resistance, a short to ground, short to voltage, or an open circuit, the same fault code will appear. Use a 12v probe with a test light to check the boost solenoid wiring.

As the complete boost solenoid circuit is under the hood of your car, check for moisture and corrosion at the connectors and along the wiring. Any moisture or corrosion in the connector can cause a poor connection that can set DTC P0034.

Short to Ground

Attach one lead of your probe to a bare ground. Disconnect the boost solenoid connector from the solenoid. With the ignition in the on position and the engine not running, probe the positive wire at the solenoid. There should be power at the positive wire, indicated by the test light on your probe illuminating. If the test light does not illuminate or is dim, trace the positive wire back to the PCM looking for a short to ground.

Short to Voltage

Attach one lead of your test probe to the positive battery terminal. With the ignition on and the engine not running, probe the negative or ground circuit at the boost solenoid connector. The test light should illuminate if ground is present. If ground is not present, trace the wire back to the PCM and repair any damaged, cracked, or broken sections of wire.

While checking for a short to ground or voltage, perform a wiggle test along each wire to help determine if there is a short. Keep close watch on the bulb, noting any changes when the wire is wiggled. Repair the wiring as necessary at any section that causes the bulb to go out.

Check the PCM

The control module supplies voltage and a ground to the boost solenoid. Test the PCM with the key on, engine off. With the test probe lead connected to a ground, probe the positive wire at the PCM connector. If the test light illuminates, the positive circuit is good. If it does not illuminate, the PCM is faulty. Test the ground circuit with the test probe lead connected to the positive battery terminal. If the test light illuminates, the ground circuit is good. If the test light does not light up, the PCM is faulty and needs to be replaced.

Searches related to P0034

p0035
turbocharger bypass valve control circuit
p0033
p0032
p0036
p0037
p0304