Vauxhall Workshop Service and Repair Manuals

DTC P0234 or P0299 - LLU

Diagnostic Instructions

DTC Descriptors

Diagnostic Fault Information

Typical Scan Tool Data

Boost Pressure Sensor

Circuit/System Description

The boost pressure sensor is integrated with the inlet air temperature (IAT) sensor. The boost pressure sensor measures the range of pressures between the turbocharger and the throttle body. The sensor used on this engine is a three atmosphere sensor. Pressure in this portion of the induction system is affected by engine speed, throttle opening, turbocharger boost pressure, inlet air temperature (IAT), barometric pressure (BARO) and the efficiency of the charge air cooler. The boost pressure sensor and integrated intake air temperature (IAT) sensor have the following circuits:

The boost pressure sensor provides a signal voltage to the engine control module (ECM), relative to the pressure changes, on the inlet air pressure signal circuit. Under normal operation the greatest pressure that can exist in this portion of the induction system at ignition ON, engine OFF is equal to the BARO. When the vehicle is operated at wide open throttle (WOT), the turbocharger can increase the pressure to near 240 kPa (34.80 PSI). The least pressure that occurs is when the vehicle is idling or decelerating and it is equal to the BARO.

Conditions for Running the DTC

P0234 00

P0299 00

Conditions for Setting the DTC

P0234 00

The ECM detects that the actual boost pressure is greater than the desired boost pressure for longer than 2 s.

P0299 00

The ECM detects that the actual boost pressure is less than the desired boost pressure continuously.

Action Taken When the DTC Sets

Conditions for Clearing the DTC

DTCs P0234 00 and P0299 00 are Type C DTCs.

Diagnostic Aids

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Verify that restrictions do not exist in the exhaust system. Refer to Restricted Exhaust .
2. If DTC P0299 00 is set, verify the proper operation of the charge air bypass valve.
3. Use the scan tool output controls to command the Turbocharger Bypass Solenoid Valve to active and then back to inactive. An audible series of clicks should be heard and felt.
4. Use the scan tool output controls to command the Turbocharger Wastegate Solenoid Valve to 100% and then back to 0%. An audible series of clicks should be heard and felt between 20-90%.
5. Determine the current vehicle testing altitude. Ignition ON, observe the scan tool manifold absolute pressure (MAP) Sensor parameter, the Boost Pressure Sensor parameter, and the BARO Sensor parameter. Compare the parameters to each other and to the Altitude Versus Barometric Pressure table.
6. Use the scan tool and compare the MAP Sensor parameter to the Boost Pressure Sensor parameter during a WOT acceleration. The readings should be within 20 kPa (2.9 PSI) of each other.
7. 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. Verify the integrity of the entire air induction system including all turbocharger components by inspecting for the following conditions:

•	Any damaged components, including the turbocharger, the charge air cooler, and the Q42 Turbocharger Wastegate Solenoid Valve

•	Any hairline fractures of the B65 Intake Manifold Pressure and Air Temperature Sensor housing

•	Loose or improper installation of any components

•	An air flow restriction

•	Any vacuum leak

•	Any pinholes or breaks in the vacuum hoses attached to the Q42 Turbocharger Wastegate Solenoid Valve

•	Any restrictions in the vacuum hoses attached to the Q42 Turbocharger Wastegate Solenoid Valve

•	Improper routing or connecting of the vacuum hoses on the charge air cooler, the Q40 Turbocharger Bypass Solenoid Valve, and the Q42 Turbocharger Wastegate Solenoid Valve

•	Any type of air leak between the turbocharger and the throttle body, including the charge air cooler assembly

•	Verify that an exhaust leak does not exist, including the mating surface area between the turbocharger and the exhaust manifold.

2. Ignition OFF, disconnect the harness connector at the B65 Intake Manifold Pressure and Air Temperature Sensor.
3. Ignition OFF for 90 s, test for less than 5 Ω between the low reference circuit terminal 1 and ground.

⇒	If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

4. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 3 and ground.

⇒	If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

⇒	If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.

5. Verify the scan tool Boost Pressure Sensor parameter is less than 1 kPa (0.14 PSI).

⇒	If greater than the specified range, test the signal circuit terminal 4 for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module.

6. Install a 3 A fused jumper wire between the signal circuit terminal 4 and the low reference circuit terminal 1. Verify the scan tool Boost Pressure Sensor is greater than 260 kPa (37.7 PSI).

⇒	If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

7. If all circuits/connections test normal, replace the B65 Intake Manifold Pressure and Air Temperature Sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.