DTC P0234 or P0299 - LBY
Diagnostic Instructions
DTC Descriptors
DTC P0234 00: Engine Overboost
DTC P0299 00: Engine Underboost
Circuit/System Description
The turbocharger pressure sensor responds to pressure changes in
the inlet 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 an 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 00
The actual turbocharger boost pressure is greater than the
desired range for greater than 6 s.
P0299 00
The actual turbocharger boost pressure is less than the desired
range for greater than 6 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
- 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).
- Observe the DTC information with a scan tool. Verify
that DTC P0045, P0047, or P0048 are not set.
- Engine running, increase the engine speed to
2 000 RPM. Command the Boost Pressure Actuator LPT ON and
OFF with a scan tool. Verify the scan tool Boost Pressure Sensor
parameter increases and decreases with the scan tool commands.
- Engine running, increase the engine speed to
2 000 RPM. Command the Boost Pressure Actuator HPT ON and
OFF with a scan tool. Verify the scan tool Boost Pressure Sensor
parameter increases and decreases with the scan tool commands.
- 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
- Inspect the fuel tank for the right fuel content.
- Inspect the inlet, and the exhaust systems, for the
following:
• |
Damaged or missing components |
⇒ |
If a condition is found, repair as necessary. |
- Disconnect the vacuum source from the
Q42A Turbocharger 1 Wastegate Solenoid Valve.
- Connect the EN 23738-A Mityvac to the
Q42A Turbocharger 1 Wastegate 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. |
- Connect the vacuum source to the
Q42A Turbocharger 1 Wastegate Solenoid Valve. Connect the
EN 23738-A Mityvac to the Q42A Turbocharger 1
Wastegate Solenoid Valve vacuum port. Engine running, command the
Q42A Turbocharger 1 Wastegate Solenoid Valve 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
Q42A Turbocharger 1 Wastegate Solenoid Valve. |
- Command the Q42A Turbocharger 1 Wastegate
Solenoid Valve ON with a scan tool. Verify the vacuum is greater
than -50 kPa (-7.25 PSI).
⇒ |
If less than the specified range, replace the
Q42A Turbocharger 1 Wastegate Solenoid Valve. |
- Connect the EN 23738-A Mityvac to the
Q42A Turbocharger 1 Wastegate Solenoid Valve vacuum actuator
hose. Apply -50 kPa (-7.25 PSI) vacuum, verify the
Turbocharger By Pass rod is moving.
⇒ |
If less than the specified range, inspect the
vacuum hose for a leak or restriction. If the supply hose is
normal, replace the Q42A Turbocharger 1 Wastegate Solenoid
Valve vacuum actuator. |
- Disconnect the vacuum source from the
Q42B Turbocharger 2 Wastegate Solenoid Valve.
- Connect the EN 23738-A Mityvac to the
Q42B Turbocharger 2 Wastegate 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. |
- Connect the vacuum source to the
Q42A Turbocharger 1 Wastegate Solenoid Valve. Connect the
EN 23738-A Mityvac to the Q42B Turbocharger 2
Wastegate Solenoid Valve vacuum port. Engine running, command the
Q42B Turbocharger 2 Wastegate Solenoid Valve 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
Q42B Turbocharger 2 Wastegate Solenoid Valve. |
- Command the Q42B Turbocharger 2 Wastegate
Solenoid Valve ON with a scan tool. Verify the vacuum is greater
than -50 kPa (-7.25 PSI).
⇒ |
If less than the specified range, replace the
Q42B Turbocharger 2 Wastegate Solenoid Valve. |
- Connect the EN 23738-A Mityvac to the
Q42B Turbocharger 2 Wastegate Solenoid Valve vacuum actuator
hose. Apply -50 kPa (-7.25 PSI) vacuum, verify the
Turbocharger By Pass rod is moving.
⇒ |
If less than the specified range, inspect the
vacuum hose for a leak or restriction. If the supply hose is
normal, replace the Q42B Turbocharger 2 Wastegate Solenoid
Valve vacuum actuator. |
- Inspect the turbocharger oil supply lines for a
restriction.
⇒ |
If restricted, repair or replace as
necessary. |
- If all other components test normal, replace the
turbocharger.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
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