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. This is a type B DTC.
Conditions for Setting the DTC
| • | Engine speed greater than 2400 RPM. |
| • | Fuel rate greater than 20 mm. |
| • | Boost pressure less than or equal to 20 kPa from desired (internal to PCM). |
| • | Conditions met for 10 seconds. |
or
| • | Engine speed greater than 1800 but less than 2400 RPM. |
| • | Fuel rate greater than 20 mm. |
| • | Boost pressure less than or equal to (110 kPa) - ((100 kPa - BARO)/2) (internal to PCM). |
| • | Conditions met for 2 seconds. |
Action Taken When the DTC Sets
| • | Poor performance |
| • | Reduce maximum fuel. |
| • | No 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 when forty consecutive warm-up cycles that the diagnostic does not fail (coolant temperature has risen 5°C (40°F) from start up coolant temperature and engine coolant temperature exceeds 71°C (160°F) that same ignition cycle. |
| • | Use of a Scan Tool |
Diagnostic Aids
A vacuum leak or a pinched vacuum line may cause a DTC P0236. Check all vacuum lines and components connected to the hoses for leaks or sharp bends. Check vacuum source. A possible EGR DTC will store if there is a problem with the vacuum source. Also check for proper vacuum line routing. This diagnostic checks for a skewed sensor.
Test Description
Number(s) below the Step number(s) on the Diagnostic Table.
-
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.
-
This step checks the turbocharger wastegate actuator for vacuum leaks. The actuator must hold vacuum.
-
This step will check for vacuum leaks at the lines.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 |
Important: Before clearing DTCs use the scan tool Capture Info to record freeze frame and failure records for reference, as data will be lost when Clear Info function is used. Was the On-Board Diagnostic (OBD) System Check performed? | -- | ||||||||
2 |
Is the vacuum greater than or equal to the specified value? | 15 in. Hg | ||||||||
Is the vacuum greater than the specified value? | 1 in. Hg | |||||||||
Does the turbocharger wastegate actuator hold vacuum? | -- | |||||||||
Was a problem found? | -- | |||||||||
6 | Does the turbocharger wastegate actuator arm move freely? | -- | ||||||||
7 | DTC is intermittent. If no additional DTCs are stored, refer to Diagnostic Aids. If additional DTCs were stored, refer to those table(s). Are additional DTCs stored? | -- | Go to the Applicable DTC Table | Go to Diagnostic Aids | ||||||
8 | Check the vacuum pump for proper output (refer to Engine Mechanical). | -- | -- | |||||||
9 | Check for a plugged wastegate solenoid filter. Repair as necessary. Is the wastegate solenoid filter plugged? | -- | ||||||||
10 | Replace the wastegate solenoid. Is the action complete? | -- | -- | |||||||
11 | Replace the turbocharger wastegate actuator. Is the action complete? | -- | -- | |||||||
12 |
Does the Scan Tool indicate that this diagnostic Ran and Passed? | -- | ||||||||
13 | Using the Scan Tool, select Capture Info, Review Info. Are any DTCs displayed that have not been diagnosed? | -- | Go to the Applicable DTC Table | System OK |
