Buick Regal: DTC P0201-P0204, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P1248, P1249, P124A, P124B, P2147, P2148, P2150, P2151, P2153, P2154, P2156, or P2157

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 P0201

Cylinder 1 Injector Control Circuit

DTC P0202

Cylinder 2 Injector Control Circuit

DTC P0203

Cylinder 3 Injector Control Circuit

DTC P0204

Cylinder 4 Injector Control Circuit

DTC P0261

Cylinder 1 Injector Control Circuit Low Voltage

DTC P0262

Cylinder 1 Injector Control Circuit High Voltage

DTC P0264

Cylinder 2 Injector Control Circuit Low Voltage

DTC P0265

Cylinder 2 Injector Control Circuit High Voltage

DTC P0267

Cylinder 3 Injector Control Circuit Low Voltage

DTC P0268

Cylinder 3 Injector Control Circuit High Voltage

DTC P0270

Cylinder 4 Injector Control Circuit Low Voltage

DTC P0271

Cylinder 4 Injector Control Circuit High Voltage

DTC P1248

Cylinder 1 Injector High Control Circuit Shorted to Control Circuit

DTC P1249

Cylinder 2 Injector High Control Circuit Shorted to Control Circuit

DTC P124A

Cylinder 3 Injector High Control Circuit Shorted to Control Circuit

DTC P124B

Cylinder 4 Injector High Control Circuit Shorted to Control Circuit

DTC P2147

Cylinder 1 Injector High Control Circuit Low Voltage

DTC P2148

Cylinder 1 Injector High Control Circuit High Voltage

DTC P2150

Cylinder 2 Injector High Control Circuit Low Voltage

DTC P2151

Cylinder 2 Injector High Control Circuit High Voltage

DTC P2153

Cylinder 3 Injector High Control Circuit Low Voltage

DTC P2154

Cylinder 3 Injector High Control Circuit High Voltage

DTC P2156

Cylinder 4 Injector High Control Circuit Low Voltage

DTC P2157

Cylinder 4 Injector High Control Circuit High Voltage

Diagnostic Fault Information

Circuit/System Description

The engine control module (ECM) supplies voltage to each fuel injector on the high control circuits. The ECM energizes each fuel injector by grounding the low control circuit of the fuel injector. The ECM monitors the status of the fuel injector circuits. When a fuel injector circuit condition is detected by the ECM, the affected fuel injector (s) is disabled.

Conditions for Running the DTC

• DTC P062B is not set.
• The engine is running for greater than 5 s.
• The ignition voltage is greater than 11 V.
• The DTCs run continuously once the above conditions are met.

Conditions for Setting the DTC

P0201, P0202, P0203, or P0204

The ECM detects the fuel injector control circuit is open for greater than 2 s.

P0261, P0264, P0267, or P0270

The ECM detects the fuel injector control - circuit is shorted to ground for greater than 2 s.

P0262, P0265, P0268, or P0271

The ECM detects the fuel injector control + circuit is shorted to voltage for greater than 2 s.

P1248, P1249, P124A, or P124B

The ECM detects the fuel injector control + circuit is shorted to the fuel injector control - circuit for greater than 2 s.

P2147, P2150, P2153, or P2156

The ECM detects the fuel injector control + circuit is shorted to ground for greater than 2 s.

P2148, P2151, P2154, or P2157

The ECM detects the fuel injector control + circuit is shorted to voltage for greater than 2 s.

Action Taken When the DTC Sets

DTCs P0201, P0202, P0203, P0204, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P1248, P1249, P124A, P124B, P2147, P2148, P2150, P2151, P2153, P2154, P2156, and P2157 are Type A DTCs.

Conditions for Clearing the DTC

DTCs P0201, P0202, P0203, P0204, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P1248, P1249, P124A, P124B, P2147, P2148, P2150, P2151, P2153, P2154, P2156, and P2157 are Type A DTCs.

Diagnostic Aids

• Performing the fuel injector coil test may help isolate an intermittent condition. Refer to Fuel Injector Diagnosis.
• If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the scan tool Injector Control Circuit Status parameters. An Injector Control Circuit Status parameter will change from OK or Not Run to Malfunction if there is a condition with the circuit or a connection.

Reference Information

Schematic Reference

Engine Controls Wiring Schematics (LTG)

Connector End View Reference

Component Connector End View Index

Powertrain Component View

Powertrain Component Views

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

NOTE: The engine must be running for the scan tool Cylinder 1 - 4 Injector Control Circuit Status parameters to function.

3. Engine idling.

4. Verify with a scan tool the parameters listed below do not increment.

• Cylinder 1 Current Misfire Counter
• Cylinder 2 Current Misfire Counter
• Cylinder 3 Current Misfire Counter
• Cylinder 4 Current Misfire Counter
• If a parameter increments

Refer to Circuit/System Testing.

• Go to next step: If a parameter does not increment

5. Verify with a scan tool the parameters listed below display OK or Not Run.

• Cylinder 1 Injector Control Circuit Status
• Cylinder 2 Injector Control Circuit Status
• Cylinder 3 Injector Control Circuit Status
• Cylinder 4 Injector Control Circuit Status
• If OK or Not Run is not displayed

Refer to Circuit/System Testing.

• Go to next step: If OK or Not Run is displayed

6. 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.

7. Verify the DTC does not set

• If the DTC sets

Refer to Circuit/System Testing.

• Go to next step: If the DTC does not set

8. All OK.

Circuit/System Testing

1. Ignition OFF, all vehicle systems OFF, disconnect the harness connector at the K20 Engine Control Module. It may take up to 2 min for all vehicle systems to power down.

2. Test for infinite resistance between the appropriate Q17 Fuel Injector control + circuit and ground.

• If less than infinite resistance

1. Disconnect the harness connector of the Q17 Fuel Injector.
2. Test for infinite resistance between the Q17 Fuel Injector control + circuit and ground.
   • If less than infinite, repair the short to ground in the circuit.
   • Go to next step: If infinite resistance
3. Test for infinite resistance between the Q17 Fuel Injector control - circuit and ground.
   • If less than infinite, repair the short to ground in the circuit.
   • If infinite, replace the Q17 Fuel Injector.

• Go to next step: If infinite resistance

3. Ignition ON.

4. Test for less than 1 V between the Q17 Fuel Injector control + circuit and ground.

• If 1 V or greater

1. Disconnect the harness connector of the Q17 Fuel Injector, ignition ON.
2. Test for less than 1 V between the Q17 Fuel Injector control + circuit and ground.
   • If 1 V or greater, repair the short to voltage on the circuit.
   • If less than 1 V, repair the short to voltage on the control - circuit.

• Go to next step: If less than 1 V

5. Ignition OFF.

6. Test for less than 3 Ω between the Q17 Fuel Injector control + circuit and control - circuit.

• If 3 Ω or greater

1. Disconnect the harness connector of the Q17 Fuel Injector.
2. Test for less than 2 Ω on the control + circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • Go to next step: If less than 2 Ω
3. Test for less than 2 Ω on 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 Q17 Fuel Injector.

• Go to next step: If less than 3 Ω

7. Replace the K20 Engine Control Module.

Component Testing

Fuel Injector Diagnosis

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• Fuel Injector Replacement
• Control Module References for control module replacement, setup, and programming

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