P0238

CIRCUIT DESCRIPTION
The powertrain control module (PCM) controls boost using the turbocharger wastegate solenoid. The solenoid is pulse width modulated (PWM). When the wastegate solenoid is not energized, the vacuum to the turbocharger wastegate solenoid is vented to atmosphere through the solenoid. As the pulse width is increased by the PCM, more vacuum is applied through the solenoid to the wastegate actuator. At idle a higher vacuum to the wastegate actuator helps keep the wastegate closed. At higher engine speeds the vacuum supplied by the solenoid is less, allowing the turbocharger boost pressure to overcome the wastegate actuator.

CONDITIONS FOR RUNNING THE DTC
The engine speed is less than 3,506 RPM.

CONDITIONS FOR SETTING THE DTC
The boost pressure is more than or equal to 4.8 volts (202 kPa) .

ACTION TAKEN WHEN THE DTC SETS
^ The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and tails.
^ The control module records the operating conditions at the time the diagnostic tails. The first time the diagnostic fails, the control module stores this information in the Failure Records. It the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
^ A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
^ A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
^ Clear the MIL and the DTC with a scan tool.

DIAGNOSTIC AIDS
An intermittent can be caused by the following the following conditions:
^ Faulty connections
^ Rubbed-through wire insulation
^ A broken wire inside the insulation

Check for opens or shorts to ground in the signal wire, or for an open in the 5-volt reference circuit.

TEST DESCRIPTION

Steps 1-10:

Steps 11-16:

The numbers below refer to the step numbers on the diagnostic table.
3. This step will determine if the PCM is responding to a low signal voltage. This will indicate that the PCM is OK.
9. If the scan display is still less than or equal to 9 kPa by disconnecting the PCM the short to voltage is in the wiring.
10. If the voltmeter value stays the same by disconnecting the PCM the short to battery voltage is in the wiring.