GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The engine control module (ECM) enables the appropriate fuel injector on the intake stroke for each cylinder. Ignition voltage is supplied directly 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 DTC sets.

Conditions for Running the DTC

    • The engine speed is more than 40 RPM.
    • The system voltage is between 7.5-15 volts.

Conditions for Setting the DTC

    • The ECM detects an incorrect voltage on the fuel injector control circuit.
    • The condition exists for 30 seconds.

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 Coil Test may help isolate an intermittent condition. Refer to Fuel Injector Solenoid Coil Test .
    • If the condition is intermittent, refer to Intermittent Conditions .

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step verifies that the condition is present.

  2. This step verifies that the ECM is able to control the fuel injector. If the test lamp flashes, the ECM and the wiring are OK.

  3. This step isolates the circuit between the multi-way connector and the ECM. An open on the fuel injector control circuit will not allow the test lamp to flash.

  4. This step inspects for fuel injector harness damage between the multi-way connector and the intake plenum. Careful inspection may isolate the condition before removal of the intake plenum.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

Important: If DTCs P0201, P0202, P0203, P0204, P0205, and P0206 are all set, inspect the battery positive voltage supply circuit for an open between the underhood bussed electrical center (UBEC) and the splice.

  1. Clear the DTCs with a scan tool.
  2. Crank the engine or start the engine.

Does an injector DTC set?

Go to Step 4

Go to Step 3

3

  1. Observe the Freeze Frame/Failure Records data for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Crank the engine or start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text or as close to the Freeze Frame/Failure Records data that you observed.

Does the DTC fail this ignition?

Go to Step 4

Go to Diagnostic Aids

4

  1. Turn OFF the ignition.
  2. Disconnect the fuel injector harness multi-way connector.
  3. Probe the appropriate fuel injector control circuit, engine control module (ECM) side, with a test lamp connected to B+.
  4. Crank the engine.

Does the test lamp flash while cranking the engine?

Go to Step 6

Go to Step 5

5

Test the control circuit of the fuel injector for an open between the multi-way connector and the ECM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 16

Go to Step 12

6

  1. Turn ON the ignition, with the engine OFF.
  2. Probe the ignition 1 voltage supply circuit with a test lamp connected to a good ground.

Does the test lamp illuminate?

Go to Step 7

Go to Step 13

7

  1. Inspect the accessible fuel injector jumper harness between the multi-way connector and the intake plenum for the following:
  2. • Poor connections at the multi-way connector
    • Damaged or pinched wiring
    • Broken wires inside the insulation
  3. Repair as necessary. Refer to Wiring Repairs and Repairing Connector Terminals in Wiring Systems.

Did you find and correct the condition?

Go to Step 16

Go to Step 8

8

Test for continuity between the ignition 1 voltage supply and the appropriate fuel injector control circuit, fuel injector side, at the multi-way connector with the DMM. Refer to Testing for Continuity in Wiring Systems.

Does the DMM indicate OL?

Go to Step 9

Go to Step 11

9

Test the control circuit of the fuel injector for an open between the multi-way connector and the injector connector. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 16

Go to Step 10

10

Test the ignition 1 voltage supply circuit of the affected fuel injector for an open between the fuel injector and the splice. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 16

Go to Step 11

11

Test for an intermittent and for a poor connection at the fuel injector. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems.

Did you find and correct the condition?

Go to Step 16

Go to Step 14

12

Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems.

Did you find and correct the condition?

Go to Step 16

Go to Step 15

13

Repair the ignition 1 voltage supply circuit of the fuel injector for an open. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 16

--

14

Replace the fuel injector. Refer to Fuel Injector Replacement and Fuel Injector and Fuel Rail Replacement .

Did you complete the replacement?

Go to Step 16

--

15

Replace the ECM. Refer to Engine Control Module Replacement .

Did you complete the replacement?

Go to Step 16

--

16

  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  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.

Did the DTC fail this ignition?

Go to Step 2

Go to Step 17

17

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK