P0236

DTC P0236 TC Boost System






Circuit Description

The PCM operates a solenoid to the control boost. This solenoid is normally open. By providing a ground path, the PCM energizes the solenoid which then allows a vacuum to pass to the wastegate valve. During normal operation, the PCM compares the wastegate duty cycle signal with the boost signal and makes corrections in the duty cycle accordingly.

Conditions for Running the DTC

^ The engine speed is greater than 2400 RPM.
^ The fuel rate is greater than 20 mm. or
^ The engine speed is greater than 1800 but less than 2400 RPM.
^ The fuel rate is greater than 20 mm.

Conditions for Setting the DTC

^ The boost pressure is greater than, less than, or equal to 20 kPa from desired (internal to PCM).
^ All diagnostic set conditions met for 10 seconds.

Action Taken When the DTC Sets

^ A poor performance condition will exist.
^ The PCM will reduce maximum fuel
^ The PCM will disable the torque converter clutch (TCC).

Conditions for Clearing the MIL/DTC

^ The PCM will turn the MIL OFF after three consecutive trips without a fault condition.
^ A History DTC will clear after forty consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.
^ The use of a scan tool will clear the DTC codes.

Diagnostic Aids

A vacuum leak or a pinched vacuum line may cause a DTC P0236. Check all of the vacuum lines and the components connected to the hoses for any leaks or sharp bends. Check the vacuum source. Also check for a proper vacuum line routing.

The turbocharger actuator uses a pulse width modulated vacuum solenoid that causes the vacuum to fluctuate under normal conditions. A steady vacuum reading indicates a restricted solenoid vent filter or a solenoid vent orifice.

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

4. This will check the wastegate solenoid and filter. If the filter is plugged, the filter will not allow the solenoid to vent and this will cause an overboost condition.
5. This step checks the turbocharger wastegate actuator for vacuum leaks. The actuator must hold vacuum.
6. This step will check for vacuum leaks at the lines.
9. This step will check for a skewed boost pressure sensor.