DTC P0234 or P0299 (LPL or LPV)
Diagnostic Instructions
DTC Descriptors
| DTC P0234: Engine Overboost |
| DTC P0299: Engine Underboost |
Circuit/System Description
The turbocharger pressure sensor responds to pressure changes in
the intake manifold. The pressure changes occur based on the engine
load, and turbocharger boost. The engine control module (ECM)
supplies 5 V to the turbocharger pressure sensor on the 5 V
reference circuit. The ECM provides a ground on the low reference
circuit. The turbocharger pressure sensor provides a signal to the
ECM on the signal circuit which is relative to the pressure changes
in the manifold.
Conditions for Running the DTC
| • |
The DTCs run continuously when
the above conditions are met. |
Conditions for Setting the DTC
P0234
The actual turbocharger boost pressure is greater than the desired
range for greater than 7 s.
P0299
The actual turbocharger boost pressure is less than the desired
range for greater than 7 s.
Action Taken When the DTC Sets
DTCs P0234 and P0299 are Type B DTCs.
Conditions for Clearing the DTC
DTCs P0234 and P0299 are Type B DTCs.
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Special Tools
EN 23738-A Mityvac
For equivalent regional tools, refer to
Special Tools .
Circuit/System Verification
| 1. |
Ignition ON, compare the scan
tool Boost Pressure Sensor parameter to the Barometric Pressure
(BARO) parameter. Both parameters should be within 5 kPa (0.72
PSI). |
| 2. |
Observe the DTC information
with a scan tool. Verify that DTC P0047 or P0048 are not
set. |
| 3. |
Engine running, increase the
engine speed to 2 000 RPM. Command the Turbocharger Vane Position
ON and OFF with a scan tool. Verify the scan tool Boost Pressure
Sensor parameter increases and decreases with the scan tool
commands. |
| 4. |
Operate the vehicle within the
Conditions for Running the DTC to verify the DTC does not reset.
You may also operate the vehicle within the conditions that you
observed from the Freeze Frame/Failure Records data. |
Circuit/System Testing
| 1. |
Inspect the fuel tank for the
right fuel content. |
| 2. |
Inspect the intake, and the
exhaust systems, for the following: |
| |
• |
Damaged or missing
components |
| ⇒ |
If a condition is found, repair as necessary. |
| 3. |
Disconnect the vacuum source
from the Q41 Turbocharger Vane Position Control Solenoid
Valve. |
| 4. |
Connect the EN
23738-A Mityvac to the Q41 Turbocharger Vane Position
Control Solenoid Valve vacuum supply hose. Engine running, verify
the vacuum is greater than -50 kPa (-7.25 PSI). |
| ⇒ |
If less than the specified range, inspect the
vacuum supply hose and filter for a leak or restriction. If the
supply hose is normal, replace the vacuum pump. |
| 5. |
Connect the vacuum source to
the Q41 Turbocharger Vane Position Control Solenoid Valve. Connect
the EN 23738-A Mityvac to the Q41 Turbocharger Vane
Position Control Solenoid Valve vacuum port on the Q41 Turbocharger
Vane Position Control Solenoid Valve. Engine running, command the
Turbocharger Vane Position to 5% with a scan tool. Verify the
vacuum is between 0 to -40 kPa (0-5.8 PSI). |
| ⇒ |
If greater than the specified range, replace the
Q41 Turbocharger Vane Position Control Solenoid Valve. |
| 6. |
Command the Turbocharger Vane
Position ON with a scan tool. Verify the vacuum is greater than -50
kPa (-7.25 PSI). |
| ⇒ |
If less than the specified range, replace the Q41
Turbocharger Vane Position Control Solenoid Valve. |
| 7. |
Inspect the turbocharger oil
supply lines for a restriction. |
| ⇒ |
If restricted, repair or replace as
necessary. |
| 8. |
If all other components test
normal, replace the turbocharger. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|
