GM Service Manual Online
For 1990-2009 cars only

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 P2146: Injector Positive Voltage Control Circuit Group 1

DTC P2147: Injector Positive Voltage Control Circuit Group 1 Low Voltage

DTC P2148: Injector Positive Voltage Control Circuit Group 1 High Voltage

DTC P2149: Injector Positive Voltage Control Circuit Group 2

DTC P2150: Injector Positive Voltage Control Circuit Group 2 Low Voltage

DTC P2151: Injector Positive Voltage Control Circuit Group 2 High Voltage

Diagnostic Fault Information

Circuit

Short to Ground

Open

Short to Voltage

Fuel Injector Positive Voltage Supply Group 1

P2147

P2146

P2148

Fuel Injector Positive Voltage Supply Group 2

P2150

P2149

P2151

Cylinder #1 Fuel Injector Control

P2147

P0201

P2148

Cylinder #2 Fuel Injector Control

P2147

P0202

P2148

Cylinder #3 Fuel Injector Control

P2147

P0203

P2148

Cylinder #4 Fuel Injector Control

P2150

P0204

P2151

Cylinder #5 Fuel Injector Control

P2150

P0205

P2151

Cylinder #6 Fuel Injector Control

P2150

P0206

P2151

Circuit/System Description

The engine control module (ECM) calculates the optimum fuel injection on timing using data sent from various engine sensors. The common 1 injector drive circuit is a high voltage, near 120 volts, which drives injectors for cylinder 1, 2, and 3 in conjunction with the ECM grounding the fuel injector solenoid control circuit. The common 2 injector drive circuit which drives injectors for cylinder 4, 5, and 6 in conjunction with the ECM grounding the fuel injector solenoid control circuit. If the fuel injector solenoid control circuit is shorted to injector drive circuit, DTCs P0261, P0264, P0267, P0270, P0273, or P0276 will set, depending upon which cylinder fuel injector circuit failed. The injectors are separated into the following four groups:

    • Group 1--Injectors 1 to 3, or cylinder #1 to 3 injectors
    • Group 2--Injectors 4 to 6, or cylinder #4 to 6 injectors

Conditions for Running the DTC

P2146, P2147, P2149, P2150, P2151

    • The engine is running.
    • The battery voltage is between 10-16 volts.
    • The ignition switch is ON.

Conditions for Setting the DTC

P2146

The ECM detects that the common 1 fuel injector drive circuit is open during 8 engine rotations.

P2147

The ECM detects that the common 1 fuel injector drive circuit is shorted to ground during 8 engine rotations.

P2148

The ECM detects that the common 1 fuel injector drive circuit is shorted to voltage during 8 engine rotations.

P2149

The ECM detects that the common 1 fuel injector drive circuit is shorted to ground during 8 engine rotations.

P2150

The ECM detects that the common 1 fuel injector drive circuit is shorted to ground during 8 engine rotations.

P2151

The ECM detects that the common 1 fuel injector drive circuit is shorted to voltage during 8 engine rotations.

Action Taken When the DTC Sets

DTCs P2146, P2147, P2148, P2149, P2150 and P2151 are Type A DTCs.

Conditions for Clearing the DTC

DTCs P2146, P2147, P2148, P2149, P2150 and P2151 are Type A DTCs.

Diagnostic Aids

An incorrectly installed fuel injector or fuel injector harness will cause this DTC to set.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

    •  Engine Controls Component Views
    •  Engine Control Module Connector End Views

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

    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Verification

Important: If DTC P2146, P2147, P2149, P2150 or P2151 are set, test and repair those DTCs first.

Verify the integrity of the fuel injector by inspecting for the following conditions:

    • Damaged components
    • Loose or improper installation

Circuit/System Testing

Important: Observe the DTC information with a scan tool. If DTC P2146, P2147, P2149, P2150 or P2151 are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .

Important: You must perform Circuit/System Verification before proceeding with Circuit/System Testing.

One Fuel Injector DTC Sets

  1. Disconnect the affected fuel injector connector.
  2. Disconnect the ECM connector.
  3. Turn ON the ignition with the engine OFF. Connect a test lamp between the affected fuel injector control circuit and a ground.
  4. If the test lamp illuminates, test the injector control circuit for a short to voltage.
  5. Test the affected fuel injector circuit for the following:
  6. • An open between the ignition position voltage control circuit splice and the fuel injector connector
    • An open between the ECM and the ignition positive voltage control circuit splice
  7. Test the affected fuel injector for high resistance. Refer to Component Testing in this diagnostic.
  8. If the circuit does not have a short to voltage or an open, replace the ECM.

Two or More Fuel Injector DTCs Set

  1. Test the affected group injector positive voltage control circuit for an open.
  2. Test the affected fuel injector for high resistance. Refer to Component Testing in this diagnostic.
  3. If the circuit does not have an open, replace the ECM.

Component Testing

The injector solenoid coil resistance is about 2 ohms.

If resistance is more than 2 ohms or less than 1.8 ohms at 20°C (68°F), the injector for an open/high resistance. If the tests normal, replace the fuel injector.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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