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: Cylinder No. 1 Fuel Injector

DTC P0202: Cylinder No. 2 Fuel Injector

DTC P0203: Cylinder No. 3 Fuel Injector

DTC P0204: Cylinder No. 4 Fuel Injector

DTC P0205: Cylinder No. 5 Fuel Injector

DTC P0206: Cylinder No. 6 Fuel Injector

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

P2150

Cylinder #1 Fuel Injector Control

P2147

P0201

P0201, P0261, P2148

Cylinder #2 Fuel Injector Control

P2147

P0202

P0202, P2148

Cylinder #3 Fuel Injector Control

P2147

P0203

P0203, P2148

Cylinder #4 Fuel Injector Control

P2150

P0204

P0204, P2148

Cylinder #5 Fuel Injector Control

P2150

P0205

P0205, P2148

Cylinder #6 Fuel Injector Control

P2150

P0206

P0206, P2148

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 cylinders 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. The ECM also supplies 12 volts at all times to the injector control circuit in order to verify circuit integrity. If the fuel injector solenoid control circuit is shorted to injector drive circuit, DTC 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--cylinder #1 to 3 injectors
    • Group 2--cylinder #4 to 6 injectors

Conditions for Running the DTC

    • The battery voltage is between 10-16 volts.
    • The ignition is ON for longer than 2 seconds.

Conditions for Setting the DTC

    • The ignition switch is OFF for longer than 2 seconds.
    • The ECM detects an injector output open or short condition.

Action Taken When the DTC Sets

DTCs P0201, P0202, P0203, P0204, P0205, and P0206 are Type A DTCs.

Conditions for Clearing the DTC

DTCs P0201, P0202, P0203, P0204, P0205, and P0206 are Type A DTCs.

Diagnostic Aids

An incorrectly installed fuel injector, intermediate connector, 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

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

    • Damaged components
    • Loose or improper installation

Circuit/System Testing

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

  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.
  9. For two or more fuel injector DTCs Set, perform the following:
  10. • Test the affected group injector positive voltage control circuit for an open.
    • Test the affected fuel injector for high resistance. Refer to Component Testing in this diagnostic.
    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