P0234

P0234-TURBOCHARGER OVERBOOST CONDITION





For a complete wiring diagram Consult Diagrams/Electrical

Theory of Operation

A target throttle inlet pressure is determined based on accelerator pedal position and other vehicle operating conditions. If the turbocharger control solenoid fails to keep the measured throttle inlet pressure between the target throttle inlet pressure and the target throttle inlet pressure plus 30 kPa for 2 seconds, the diagnostic fails. The other failure mode is if the difference between the throttle inlet pressure and the barometric pressure exceeds 220 kPa for 2 seconds. If the diagnostic fails again within 3 key cycles, the MIL is illuminated. If three ignition key cycles are accumulated without an additional failure, the pending fault is cleared.

- When Monitored:
The Turbo Overboost diagnostic is run under the following conditions: (1) The engine rpm is greater than 2500, (2) the throttle position is greater than 0.95 volts, (3) the intake manifold pressure is greater than the barometric pressure, plus 30 kPa, (4) There is fuel being delivered to the engine.

- Set Condition:
A pending fault is sent when one of the following occurs: (1) The difference between the throttle inlet pressure and the barometric pressure exceeds 220 kPa for 2 seconds, (2) The throttle inlet pressure exceeds the target throttle inlet pressure by approximately 30 kPa for 2 seconds.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.Initial Inspection and Diagnostic Overview

Diagnostic Test

1. DTC IS ACTIVE

NOTE: Diagnose and repair any related turbocharger solenoid or pressure sensor DTCs before continuing with this test.

NOTE: It may be necessary to test drive the vehicle within the DTC monitoring conditions in order to get this fault to reset.

Start the engine and allow it to reach normal operating temperature.

WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

With the scan tool, select View DTCs.
Is the status Active for this DTC?

Yes

- Go to 2

No

- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.Checking for an Intermittent DTC

2. CHECK FOR INTAKE AND EXHAUST SYSTEM RESTRICTIONS
NOTE: Damaged, restricted or poorly connected intake and turbocharger related tubes may cause this DTC to set.

Inspect all air intake, crankcase vent and turbocharger related hoses/tubes and connections.
Inspect the complete exhaust system for damaged, bent or clogged pipes that can cause exhaust system restrictions and excessive back pressure.
Were any problems found?

Yes

- Repair as necessary.
- Perform the PCM Verification Test Ver. 1Powertrain Verification Test.

No

- Go to 3

3. THROTTLE INLET PRESSURE SENSOR CIRCUIT INSPECTION
Turn the ignition off.
Disconnect the PCM harness connectors.
Disconnect the Throttle Inlet Pressure sensor harness connector.
Inspect and test each of the sensor circuits between the sensor connector and PCM harness connectors.

NOTE: Test each circuit for high resistance, a short to ground and a short to voltage.

Were any problems found?

Yes

- Repair as necessary.
- Perform the PCM Verification Test Ver. 1Powertrain Verification Test.

No

- Go to 4

4. WASTEGATE AND SOLENOID INSPECTION
NOTE: A seized or sticking Wastegate may cause this DTC to set.

Inspect the Wastegate Solenoid, linkage, and the Wastegate for proper operation.
Inspect and test each of the Wastegate solenoid vacuum circuits between the engine, the solenoid and the Wastegate.
Inspect and test each of the Wastegate solenoid electrical circuits between the solenoid connector and PCM harness connectors.

NOTE: Test each electrical circuit for high resistance, a short to ground and a short to voltage.

Were any problems found?

Yes

- Repair as necessary.
- Perform the PCM Verification Test Ver. 1Powertrain Verification Test.

No

- Repair or replace the Turbocharger.
- Perform the PCM Verification Test Ver. 1Powertrain Verification Test.