P0237

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION
The PCM operates a solenoid to control boost. This solenoid is normally open. By providing a ground path, the PCM energizes the solenoid which allows 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 to the duty cycle accordingly. This is a type B DTC.

CONDITIONS FOR SETTING THE DTC
^ The Boost Pressure is less than 40 kPa.
^ The condition was met for 2 seconds.

ACTION TAKEN WHEN THE DTC SETS
The Malfunction Indicator Lamp (MIL) will be illuminated after 2 test failures.

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 during which the diagnostic does not fail (the coolant temperature has risen 5°C (40°F) from the start up coolant temperature and the engine coolant temperature exceeds 71°C (160°F) during that same ignition cycle).
^ Use of a Scan Tool will clear the DTC codes.

DIAGNOSTIC AIDS
Very little boost can be attained by revving the engine in neutral. If the boost sensor signal circuit is open or shorted to ground, the boost solenoid will show a zero duty cycle.
An intermittent may be caused by the following:
^ Poor connections.
^ Rubbed through wire insulation.
^ Broken wire inside the insulation.

TEST DESCRIPTION
The number(s) below refer to the Step number(s) on the Diagnostic Table.
2. This Step will determine if DTC P0237 is the result of a hard failure or an intermittent condition.
3. This Step simulates conditions for a DTC P0237. If the PCM recognizes the change, the PCM and the signal circuit are OK.
9. In this step, components that share the 5 volt reference can cause the reference voltage to be shorted to ground. This can be checked by disconnecting each component one at a time, including the PCM while checking for continuity on that circuit to chassis ground.