Buick Regal: DTC P0090-P0092, P00C8, P00C9, or P00CA
Diagnostic Instructions
- Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
- Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
- Diagnostic Procedure Instructions provides an overview of each
diagnostic category.
DTC Descriptors
DTC P0090
Fuel Pressure Regulator Control Circuit
DTC P0091
Fuel Pressure Regulator Control Circuit Low Voltage
DTC P0092
Fuel Pressure Regulator Control Circuit High Voltage
DTC P00C8
Fuel Pressure Regulator High Control Circuit
DTC P00C9
Fuel Pressure Regulator High Control Circuit Low Voltage
DTC P00CA
Fuel Pressure Regulator High Control Circuit High Voltage
Diagnostic Fault Information
Circuit/System Description
The high fuel pressure necessary for direct injection is supplied by the high
pressure fuel pump. The
high pressure fuel pump is mounted on the rear of the engine and is driven by a
three-lobe cam on the
camshaft. This high pressure fuel pump also regulates the fuel pressure using an
actuator in the form of
an internal solenoid-controlled valve. In order to keep the engine running
efficiently under all operating
conditions, the engine control module (ECM) requests pressure ranging from 2 -
15 MPa (290 - 2, 176
psi), depending on engine speed and load. Output drivers in the ECM provide the
pump control circuit
with a 12 V pulse-width modulated (PWM) signal, which regulates fuel pressure by
closing and opening
the control valve at specific times during pump strokes. This effectively
regulates the portion of each
pump stroke that is delivered to the fuel rail.
It is important to note that the high pressure fuel pump is a trailing-edge
control system, meaning that if
the control solenoid is NOT powered, the pump operates at maximum flow rate. In
the event of pump
control failure, the high pressure system is protected by a relief valve in the
pump that prevents the
pressure from exceeding 17.5 MPa (2, 538 psi).
NOTE: The fuel rail pressure sensor is diagnosed separately from the
fuel
pressure control system and should not be replaced for any codes
referenced in this document.
The fuel rail fuel pressure sensor operates on a 5 V reference circuit and it
provides the feedback
necessary to the ECM to control the high pressure fuel pump and the fuel
injectors.
Conditions for Running the DTC
- The ignition voltage is greater than 11 V.
- The engine speed is greater than 50 RPM.
- The DTCs run continuously within the enabling conditions.
Conditions for Setting the DTC
P0090
- The ECM detects an open circuit in the high pressure fuel pump actuator
low control circuit.
- The DTC sets when the above condition is present for 4 s.
P0091
- The ECM detects a short to ground in the high pressure fuel pump
actuator low control circuit.
- The DTC sets when the above condition is present for 4 s.
P0092
- The ECM detects a short to voltage in the high pressure fuel pump
actuator low control circuit.
- The DTC sets when the above condition is present for 4 s.
P00C8
- The ECM detects an open circuit in the high pressure fuel pump actuator
high control circuit.
- The DTC sets when the above condition is present for 4 s.
P00C9
- The ECM detects a short to ground in the high pressure fuel pump
actuator high control circuit.
- The DTC sets when the above condition is present for 4 s.
P00CA
- The ECM detects a short to voltage in the high pressure fuel pump
actuator high control circuit.
- The DTC sets when the above condition is present for 4 s.
Action Taken When the DTC Sets
- DTCs P0090, P0091, P0092, P00C8, P00C9, and P00CA are Type A DTCs.
- A message center or an indicator displays Reduced Engine Power.
Conditions for Clearing the DTC
- DTCs P0090, P0091, P0092, P00C8, P00C9, and P00CA are Type A DTCs.
Diagnostic Aids
Reference Information
Schematic Reference
Engine Controls Wiring Schematics (LTG)
Connector End View Reference
Component Connector End View Index
Description and Operation
Fuel System Description
Electrical Information Reference
- Circuit Testing
- Connector Repairs
- Testing for Intermittent Conditions and Poor Connections
- Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify DTC P0685 or P1682 is not set.
- If any of the DTCs are set
Refer to Diagnostic Trouble Code (DTC) List - Vehicle for further
diagnosis.
- Go to next step: If none of the DTCs are set
3. Command the Fuel Pressure Regulator ON and OFF with a scan tool while
observing the
following control circuit status parameters:
- Fuel Pressure Regulator Control Circuit High Voltage Test Status
- Fuel Pressure Regulator Control Circuit Open Test Status
- Fuel Pressure Regulator Control Circuit Low Voltage Test Status
- Fuel Pressure Regulator High Control Circuit High Voltage Test Status
- Fuel Pressure Regulator High Control Circuit Open Test Status
- Fuel Pressure Regulator High Control Circuit Low Voltage Test Status
- If Malfunction is displayed
Refer to Circuit/System Testing
- Go to next step: If OK or Not Run is displayed
4. Operate the vehicle within the Conditions for Running the DTC. You may
also operate the vehicle
within the conditions that you observed from the Freeze Frame/Failure Records
data.
5. Verify the DTC does not set.
Refer to Circuit/System Testing
- Go to next step: If the DTC does not set
6. All OK
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the G18 High Pressure
Fuel Pump.
2. Ignition ON, verify that a test lamp does not illuminate between the high
control circuit terminal 1
and ground and the low control circuit terminal 2 and ground.
- If the test lamp illuminates
- Ignition OFF, disconnect the harness connector at the K20 Engine Control
Module, ignition
ON.
- Test for less than 1 V between the appropriate control circuit and
ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K20 Engine Control Module.
- Go to next step: If the test lamp does not illuminate
3. Verify that a test lamp does not illuminate between the high control
circuit terminal 1 and B+ and
the low control circuit terminal 2 and B+.
- If the test lamp illuminates
- Ignition OFF, disconnect the harness connector at the K20 Engine Control
Module.
- Test for infinite resistance between the appropriate control circuit and
ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K20 Engine Control Module.
- Go to next step: If the test lamp does not illuminate
4. Connect a 3 A fused jumper wire between the high control circuit terminal
1 and ground.
5. Verify the Fuel Pressure Regulator High Control Circuit Open Test Status
transitions from
Malfunction to OK and the Fuel Pressure Regulator High Control Circuit Low
Voltage Test Status
transitions from OK to Malfunction.
- The parameters do not change
- Ignition OFF, disconnect the harness connector at the K20 Engine Control
Module.
- Test for less than 2 Ω in the high control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K20 Engine Control Module.
- Go to next step: The parameters change
6. Connect a 3 A fused jumper wire between the low control circuit terminal 2
and B+.
7. Verify the Fuel Pressure Regulator Control Circuit Open Test Status
transitions from Malfunction
to OK and the Fuel Pressure Regulator Control Circuit High Voltage Test Status
transitions from
OK to Malfunction.
- The parameters do not change
- Ignition OFF, disconnect the harness connector at the K20 Engine Control
Module.
- Test for less than 2 Ω in the low control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K20 Engine Control Module.
- Go to next step: The parameters change
8. Test or replace the G18 High Pressure Fuel Pump.
Component Testing
1. Ignition OFF, disconnect the harness connector at the G18 High Pressure
Fuel Pump.
NOTE: The DMM and test leads must be calibrated to 0 Ω in order to
prevent misdiagnosis.
2. Test for 0.3 - 0.7 Ω at 20ºC (68ºF) between the high control circuit
terminal 1 and the low
control circuit terminal 2.
- If not between 0.3 - 0.7 Ω
Replace the G18 High Pressure Fuel Pump.
- Go to next step: If between 0.3 - 0.7 Ω
3. Test for infinite resistance between each terminal and the G18 High
Pressure Fuel Pump housing.
- If less than infinite resistance
Replace the G18 High Pressure Fuel Pump.
- Go to next step: If infinite resistance
4. All OK
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
- Fuel Pump Replacement
- Control Module References for K20 Engine Control Module replacement,
setup, and
programming
- Perform the Fuel Rail Pressure Relief Valve Reset procedure, if
supported on the scan tool.
READ NEXT:
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diag
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diag
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diag
SEE MORE:
REPAIRS AND INSPECTIONS REQUIRED AFTER A COLLISION
WARNING: Restraint systems can be damaged in a collision. To help
avoid injury and ensure that all parts in need of replacement are replaced:
Replace any seat belt system that was in use during the collision
serious enough to deploy any automati
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diagnostic Procedure Instructions provides an overview of each
diagnostic category.
DTC Descriptors
D