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 P0201: Injector 1 Control Circuit

DTC P0202: Injector 2 Control Circuit

DTC P0203: Injector 3 Control Circuit

DTC P0204: Injector 4 Control Circuit

DTC P0205: Injector 5 Control Circuit

DTC P0206: Injector 6 Control Circuit

DTC P0207: Injector 7 Control Circuit

DTC P0208: Injector 8 Control Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Ignition 1 Voltage - Fuse to Splice

P0201, P0203, P0205, P0207¹

P0201, P0203, P0205, P0207¹

--

--

Ignition 1 Voltage - Fuse to Splice

P0202, P0204, P0206, P0208¹

P0202, P0204, P0206, P0208¹

--

--

Ignition 1 Voltage - Splice to Injectors

¹,²

²

--

--

Fuel Injector 1 Control

P0201

P0201

P0201

--

Fuel Injector 2 Control

P0202

P0202

P0202

--

Fuel Injector 3 Control

P0203

P0203

P0203

--

Fuel Injector 4 Control

P0204

P0204

P0204

--

Fuel Injector 5 Control

P0205

P0205

P0205

--

Fuel Injector 6 Control

P0206

P0206

P0206

--

Fuel Injector 7 Control

P0207

P0207

P0207

--

Fuel Injector 8 Control

P0208

P0208

P0208

--

¹Open fuse

²Sets individual injector DTC

Circuit/System Description

The engine control module (ECM) enables the appropriate fuel injector pulse for each cylinder. Ignition voltage is supplied to the fuel injectors. The ECM controls each fuel injector by grounding the control circuit via a solid state device called a driver. The ECM monitors the status of each driver. If the ECM detects an incorrect voltage for the commanded state of the driver, a fuel injector control circuit DTC sets.

Conditions for Running the DTC

    • The engine is running.
    • The ignition voltage is more than 11 volts for 5 seconds.
    • DTC P0201-P0208 runs continuously when the above conditions are met.

Conditions for Setting the DTC

    • The ECM detects an incorrect voltage on the fuel injector control circuit.
    • The above condition is met for 1 second.

Action Taken When the DTC Sets

    • The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
    • The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC

    • The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
    • A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
    • Clear the MIL and the DTC with a scan tool.

Diagnostic Aids

Performing the Fuel Injector Diagnosis may help isolate an intermittent condition. Refer to Fuel Injector Diagnosis.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 34730-405 Injector Test Lamp

Circuit/System Testing

  1. Remove the engine sight shield and supercharger inlet duct assembly. Refer to Supercharger Inlet Duct Assembly Replacement.
  2. Disconnect the affected fuel injector.
  3. With the ignition ON, engine OFF, probe the ignition 1 voltage circuit of the fuel injector with a test lamp that is connected to a good ground. The test lamp should illuminate.
  4. If the test lamp does not illuminate, repair the open or the high resistance in the ignition 1 voltage circuit.
  5. Connect the J 34730-405 Test Lamp into the fuel injector connector. Start the engine.
  6. If the test lamp flashes, test for an intermittent or a poor connection at the fuel injector, or a faulty fuel injector.
    If the test lamp does not flash, test for an open, high resistance, or a short to voltage in the control circuit of the fuel injector or an intermittent or poor connection at the ECM. If the circuit tests normal, replace the ECM.
    If the test lamp remains illuminated at all times, test for a short to ground in the control circuit of the fuel injector. If the circuit tests normal, replace the ECM.

Component Testing

Note: The engine coolant temperature (ECT) sensor must be between 10-32°C (50-90°F) for an accurate measurement.

Measure for 11-14 ohms between the terminals of the injector.

If the resistance is not within the specified range, replace the injector.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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