Circuit Description
The turbocharger wastegate is a vacuum actuated valve used to control
the exhaust gas heat sent to the turbo. The wastegate pulse width modulated
solenoid meters the vacuum level at the wastegate valve actuator as
commanded by the PCM. When the PCM is commanding the wastegate solenoid
ON, the voltage at the PCM will be low (near 0 volts). When the
PCM is commanding the wastegate solenoid OFF, the voltage at the PCM
will be high (near battery voltage). The primary function of the PCM in
this circuit is to supply the ground for the wastegate solenoid. This
DTC will only diagnosis the functionality of the wastegate solenoid and
not the mechanical components of the system.
Conditions for Running the DTC
PCM requested wastegate solenoid ON (Test 1).
or
PCM requested wastegate solenoid OFF (Test 2).
Conditions for Setting the DTC
| • | Voltage on the wastegate solenoid control circuit high (near battery
voltage) (Test 1). |
| • | 2 consecutive faults detected. |
| • | Conditions met for 2 seconds. |
or
| • | Voltage on the wastegate solenoid control circuit low (near 0 volts)
(Test 2). |
| • | 2 consecutive faults detected. |
| • | Conditions met for 2 seconds. |
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) on the
second consecutive drive trip 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 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 will clear after forty consecutive warm-up
cycles, if this or any other emissions related diagnostic does not repaort
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 moduel. Ensure that the gaskets are installed correctly. The gaskets
prevent contaminate intrusion into the PCM module.
This diagnostic will set when control circuit does not follow the PCM
command (when the solenoid is requested ON voltage will drop, when the solenoid
is OFF ignition voltage will be present). The scan tool has a 5 second
ON time abort. The wastegate solenoid can be commanded ON for as many
times as needed, in 5 second intervals. Its possible DTC P0236
may set along with DTC P0243. This diagnostic can be checked
during key up. The engine will not respond to scan tool commands at
idle (the engine is unable to achieve boost pressures greater than
BARO at idle) or at any engine speed greater than idle (the PCM has
a control abort to prevent engine damage).
