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 then
allows vacuum to pass to the wastegate valve. During normal operation,
the PCM compares its wastegate duty cycle signal with the boost
signal and makes corrections in the duty cycle accordingly.
Conditions for Running the DTC
| • | The PCM performs this DTC diagnostic continuously. |
| • | Engine speed less than 3500 RPM. |
| • | Fuel rate less than 45 cu mm. |
Conditions for Setting the DTC
| • | The boost pressure is greater than or equal 202 kPa (4.86 volts). |
| • | All diagnostic set conditions met for 2 seconds. |
Action Taken When the DTC Sets
| • | The PCM will limit boost pressure. |
| • | The PCM illuminates the malfunction indicator lamp (MIL) on the
second consecutive drive trip that the diagnostic runs and fails. |
| • | The PCM records the operating conditions at the time the diagnostic
fails. The first time the diagnostic fails, the Failure Records will store
this information. If the diagnostic reports a failure on the second
consecutive drive trip, the Freeze Frame records the operating conditions
at the time of failure and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn the MIL off after three consecutive trips without
a fault condition. |
| • | A History DTC clears after forty consecutive warm-up cycles,
if this or any other emission related diagnostic does not report any failures. |
Diagnostic Aids
Important: Remove any debris from the PCM module connector surfaces before servicing
the PCM module. Inspect the PCM module connector gaskets when diagnosing/replacing
the module. Ensure that the gaskets are installed correctly.
Very little boost can be attained by revving the engine in neutral.
An intermittent may be caused by the following:
| • | Rubbed through wire insulation. |
| • | Broken wire inside the insulation. |
