GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The powertrain control module (PCM) enables the appropriate fuel injector for each cylinder. A voltage is supplied directly to the fuel injectors. The PCM controls each fuel injector by grounding the control circuit via a solid state device called a driver. The PCM monitors the status of each driver. If the PCM detects an incorrect voltage for the commanded state of the driver, a fuel injector control DTC P0201-P0206 sets.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

    • 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

Conditions for Running the DTC

    • The ignition is ON.
    • The ignition voltage is between 9-18 volts.

Conditions for Setting the DTC

    • The PCM detects an incorrect voltage on the fuel injector control circuit.
    • The condition exists for 3 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

    • A cylinder that is misfiring can also cause the misfire current counters to increment for another cylinder. Diagnose the cylinder with the highest level of misfire first.
    • Performing the Fuel Injector Coil Test may help to isolate an intermittent condition. Refer to Fuel Injector Diagnosis .
    • If the condition is intermittent, refer to Testing for Intermittent Conditions and Poor Connections .

Test Description

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

  1. This step isolates the ignition 1 voltage circuit. An open or short to ground in this circuit sets all fuel injector DTCs.

  2. This step isolates the circuit between the multi-way connector and the underhood bussed electrical center (UBEC). A short to ground will open the fuel injector fuse.

  3. This step tests if a ground is constantly being applied to the fuel injector.

  4. This step isolates the circuit between the multi-way connector and the PCM. An open or short to voltage on the fuel injector control circuit will not allow the test lamp to blink.

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

  6. This step isolates the circuit between the multi-way connector and the fuel injector. A short to voltage on the fuel injector control circuit will set this DTC.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

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

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Turn ON the ignition, with the engine OFF.
  2. Clear the DTCs with a scan tool.
  3. Attempt to start the engine.
  4. Observe the DTC info with a scan tool.

Did DTCs P0201, P0202, P0203, P0204, P0205, and P0206 set?

Go to Step 3

Go to Step 6

3

Inspect the fuel injector fuse in the underhood bussed electrical center (UBEC).

Is the fuse open?

Go to Step 4

Go to Step 5

4

  1. Turn OFF the ignition.
  2. Disconnect the fuel injector harness multi-way connector.
  3. Replace the fuel injector fuse.
  4. Turn ON the ignition, with the engine OFF.
  5. Inspect the fuel injector fuse in the UBEC.

Is the fuse open?

Go to Step 20

Go to Step 18

5

  1. Turn OFF the ignition.
  2. Disconnect the fuel injector harness multi-way connector.
  3. Connect a test lamp between the ignition 1 voltage circuit engine harness side and a good ground.
  4. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 18

Go to Step 19

6

  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Attempt to 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.

Does the DTC fail this ignition?

Go to Step 7

Go to Diagnostic Aids

7

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

Does the test lamp blink when cranking the engine?

Go to Step 11

Go to Step 8

8

Does the test lamp remain illuminated at all times?

Go to Step 10

Go to Step 9

9

Test the control circuit of the fuel injector for a short to voltage or an open between the multi-way connector and the PCM. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 24

Go to Step 17

10

Test the control circuit of the fuel injector for a short to ground between the multi-way connector and the PCM. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 24

Go to Step 23

11

Inspect the accessible fuel injector jumper harness between the multi-way connector and the plenum for the following conditions:

    • Poor connections at the multi-way connector
    • Damaged or pinched wiring
    • Broken wires inside the insulation

Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 24

Go to Step 12

12

  1. Remove the upper intake manifold. Refer to Upper Intake Manifold Removal .
  2. Probe the appropriate fuel injector control circuit, fuel injector side, at the multi-way connector, with a test lamp connected to B+.

Does the test lamp illuminate?

Go to Step 21

Go to Step 13

13

Test for continuity between the ignition voltage terminal and the appropriate fuel injector control circuit terminal, at the multi-way connector, with a DMM. Refer to Testing for Continuity .

Does the DMM indicate OL?

Go to Step 14

Go to Step 16

14

Test the control circuit of the fuel injector for an open or poor connections at the fuel injector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 24

Go to Step 15

15

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

Did you find and correct the condition?

Go to Step 24

Go to Step 22

16

Test the control circuit of the fuel injector for a short to voltage or a short to another circuit. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 24

Go to Step 22

17

Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 24

Go to Step 23

18

Repair the open or short to ground in the ignition 1 voltage circuit between the multi-way connector and the splice.

Did you complete the repair?

Go to Step 24

--

19

Repair the open in the ignition 1 voltage circuit between the multi-way connector and the UBEC. Refer to Wiring Repairs .

Did you complete the repair?

Go to Step 24

--

20

Repair the short to ground in the ignition 1 voltage circuit between the multi-way connector and the UBEC. Refer to Wiring Repairs .

Did you complete the repair?

Go to Step 24

--

21

Repair the short to ground in the fuel injector control circuit. Refer to Wiring Repairs .

Did you complete the repair?

Go to Step 24

--

22

Replace the appropriate fuel injector. Refer to Fuel Injector Replacement .

Did you complete the replacement?

Go to Step 24

--

23

Replace the PCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 24

--

24

  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 25

25

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List - Vehicle

System OK