DTC P0234 or P0299 (LUJ)
Diagnostic Instructions
DTC Descriptors
| DTC P0234 00: Engine Overboost |
| DTC P0299 00: Engine Underboost |
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
5V Reference
|
-
|
P0237 00
|
P0036 00, P0606 00
|
-
|
Signal Circuit
|
P0237 00
|
P0237 00, P0238 00
|
P0238 00
|
P0234 00, P0299 00
|
Low Reference
|
-
|
P0098 00, P0234 00, P0238 00
|
-
|
-
|
|
| |
Typical Scan Tool Data
Turbocharger Inlet Pressure Sensor Circuit
Circuit
|
Short to Ground
|
Open
|
Short to Voltage
|
Operating Conditions: Engine Running
Parameter Normal Range: BARO to 240 kPa
(34.80 PSI)
|
5V Reference
|
20-80 kPa (2.9-11.60 PSI)
|
30-80 kPa (4.35-11.60 PSI)
|
20-80 kPa (2.9-11.60 PSI)
|
Signal Circuit
|
0 kPa
|
276 kPa (40 PSI)
|
276 kPa (40 PSI)
|
Low Reference
|
-
|
276 kPa (40 PSI)
|
-
|
|
| |
Circuit/System Description
The boost pressure sensor is integrated with the intake 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, intake
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:
| • |
Intake air pressure
signal |
The boost pressure sensor provides a signal voltage to the
engine control module (ECM), relative to the pressure changes, on
the intake 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
| • |
DTCs P0237 00, or P0238 00 are
not set. |
| • |
The driver requested boost
pressure level exceeds the level of the base boost pressure.
|
| • |
This DTC runs continuously
within the enabling conditions. |
P0299 00
| • |
DTCs P0237 00, P0238 00, P0244
00, P0245 00, P0246 00, P2228 00, or P2229 00 are not set.
|
| • |
The BARO is greater than 65
kPa (9.42 PSI). |
| • |
The engine speed is between 2
600-3 120 RPM . |
| • |
The ECM is not in limp home
mode. |
| • |
The ECM is not in limp home
mode with safety fuel cut-off activated. |
| • |
The driver requested boost
pressure level exceeds the level of the base boost pressure.
|
| • |
This DTC runs continuously
within the enabling conditions. |
Conditions for Setting the DTC
P0234 00
The ECM detects that the actual boost pressure is greater than the
desired boost pressure for greater 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
| • |
DTCs P0234 00 and P0299 00 are
Type C DTCs. |
| • |
The ECM will disable boost
control and limit the system to mechanical boost only, resulting in
a substantial decrease in engine power. |
| • |
The service vehicle soon
indicator will illuminate. |
Conditions for Clearing the DTC
DTCs P0234 00 and P0299 00 are Type C DTCs.
Diagnostic Aids
| • |
The boost pressure sensor
signal circuit is pulled high in the ECM. With the sensor
disconnected, at ignition ON, a normal voltage measurement of the
signal circuit with a DMM is 5.60 V. |
| • |
The charged air cooler is
connected to the turbocharger and to the throttle body by flexible
duct work that requires the use of special high torque fastening
clamps. These clamps cannot be substituted. In order to prevent any
type of air leak when servicing the duct work, the tightening
specifications and proper positioning of the clamps is critical,
and must be strictly adhered to. |
| • |
Use a solution of dish soap
and water in a spray bottle to pinpoint any air leaks. |
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Boost Control System Description
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
| 2. |
Use the scan tool output
controls to command the Turbocharger Bypass Solenoid Valve to 100%
and then back to 0%. An audible series of clicks should be heard
and felt between 20-90%. |
| 3. |
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%. |
| 4. |
Use the scan tool and compare
the manifold absolute pressure (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. |
| 5. |
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.
|
| |
• |
Loose or improper installation
of any components |
| |
• |
An air flow restriction
|
| |
• |
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 earth. |
| ⇒ |
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
Turbocharger Inlet Pressure Sensor parameter is greater than 275
kPa (39.9 PSI). |
| ⇒ |
If less 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 Turbocharger Inlet
Pressure Sensor is less than 1 kPa (0.14 PSI). |
| ⇒ |
If greater 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.
Control Module References for ECM replacement, setup and
programming
|
