GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Express (CNG) 🢒 Engine 🢒 Engine Controls - 6.0L 🢒 DTC P0200

Circuit Description

The powertrain control module (PCM) controls fuel delivery and determines fuel system operation on bi-fuel (KL6) vehicles. The PCM is not capable of operating the high current compressed natural gas (CNG) fuel injectors. The PCM injector control signals are received by the fuel injector control module (FICM) and duplicate control signals are generated by the FICM in order to operate the CNG injectors. On bi-fuel equipped vehicles, the FICM switches off the CNG fuel injectors and re-routes the injector control signals from the PCM to the gasoline fuel injectors. A fused ignition voltage is supplied to all of the fuel injectors. The PCM monitors the status of each injector control circuit. DTC P0200 will set if there is condition on a control circuit between the PCM and FICM. On bi-fuel (KL6) vehicles, DTC P0200 can set during gasoline operation, if a circuit condition is detected between the FICM and a gasoline fuel injector.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0200 Injector Control Circuit

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC
    • The powertrain control module (PCM) detects an incorrect voltage on a fuel injector control circuit.
    • The condition exists for 5 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 on the gasoline fuel injectors may help to isolate an intermittent condition. Refer to Fuel Injector Solenoid Coil Test .
    • For an intermittent condition, refer to Intermittent Conditions .

Test Description

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

  1. Observe the fuel indicator lamp (FIL) while the engine is running in order to verify alternative fuel operation. The FIL should be OFF while the engine is running. Fill the CNG fuel tank if necessary before proceeding.

    2.

  2. The step determines if the condition occurs during gasoline operation. If the vehicle misfires while on gasoline, then the condition is between the FICM and the gasoline fuel injector.

    3.

  3. This step tests the control circuit between the PCM and the FICM. The test lamp should blink while the engine is cranking.

  4. This step verifies that an ignition voltage is supplied to the gasoline fuel injector. If the ignition voltage circuit is open DTC P0200 will set while operating on gasoline.

    5.

  5. This step tests the control circuit between the FICM and the gasoline fuel injector. A switch to gasoline is necessary in order to pulse the gasoline fuel injectors. The test lamp should blink while the engine is operating.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

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

1

Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Alternative Fuels (Engine Controls)

2

Observe the DTC information for the following DTCs:

    • P0148
    • P1209
    • P2146

Are any of the DTCs set?

Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

3

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

    3. Important: The engine must be operating on alternative fuel during this step.

  3. Idle the engine at the normal operating temperature.

    4. Important: Raise the engine idle slightly. The misfire counters may not increment with the engine at idle.

  4. Monitor the misfire current counters with a scan tool.

Are any of the misfire current counters incrementing?

Go to Step 7

Go to Step 4

4

Is this vehicle equipped with the bi-fuel option (KL6)?

Go to Step 5

Go to Step 6

5

Important: Verify that the gasoline fuel level is above 10 percent in order to prevent misdiagnosis. The misfire counters may not increment if the gasoline fuel level is below 10 percent.

  1. Force a fuel system switch-over to gasoline with the scan tool.

    2. Important: Raise the engine idle slightly. The misfire counters may not increment with the engine at idle.

  2. Monitor the misfire current counters with a scan tool.

Are any of the misfire current counters incrementing?

Go to Step 11

Go to Step 6

6
  1. Observe the Freeze Frame/Failure Records for this DTC.
  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 7

Go to Diagnostic Aids

7

  1. Turn OFF the ignition.
  2. Disconnect the harness connector of the fuel injector control module (FICM).
  3. Probe the injector control circuit from the powertrain control module (PCM), which displays the highest number of misfire current counters, with a test lamp connected to B+.
  4. Crank the engine, while observing the test lamp.

Does the test lamp blink?

Go to Step 17

Go to Step 8

8

Does the test lamp remain illuminated?

Go to Step 10

Go to Step 9

9

Test the fuel injector control circuit for an open, or a short to voltage between the PCM and the FICM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems in the G/H Van Service Manual.

Did you find and correct the condition?

Go to Step 23

Go to Step 18

10

Test the fuel injector control circuit for a short to ground between the PCM and the FICM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems in the G/H Van Service Manual.

Did you find and correct the condition?

Go to Step 23

Go to Step 22

11

  1. Turn OFF the ignition.
  2. Disconnect the harness connector of the gasoline fuel injector which displays the highest level of misfire.
  3. Probe the ignition voltage circuit of the gasoline fuel injector with a test lamp connected to a good ground.
  4. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 12

Go to Step 19

12

  1. Probe the control circuit of the gasoline fuel injector with a test lamp connected to B+.
  2. Start and idle the engine.
  3. Force a fuel system switch-over to gasoline with the scan tool.
  4. Observe the test lamp.

Does the test lamp blink?

Go to Step 16

Go to Step 13

13

Does the test lamp remain illuminated?

Go to Step 14

Go to Step 15

14

Test for a short to ground on the control circuit of the gasoline fuel injector, between the injector and the FICM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems in the G/H Van Service Manual.

Did you find and correct the condition?

Go to Step 23

Go to Step 21

15

Test for an open or short to voltage on the control circuit of the gasoline fuel injector, between the injector and the FICM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems in the G/H Van Service Manual.

Did you find and correct the condition?

Go to Step 23

Go to Step 17

16

Test for an intermittent and for a poor connection at the gasoline fuel injector. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems in the G/H Van Service Manual.

Did you find and correct the condition?

Go to Step 23

Go to Step 20

17

Test for an intermittent and for a poor connection at the FICM. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems in the G/H Van Service Manual.

Did you find and correct the condition?

Go to Step 23

Go to Step 21

18

Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems in the G/H Van Service Manual.

Did you find and correct the condition?

Go to Step 23

Go to Step 22

19

Important: The fuse also supplies voltage to the ignition coil modules. If the fuse is open, inspect all related circuits and components for a short to ground. Refer to Circuit Testing in Wiring Systems.

Repair the ignition 1 voltage circuit of the fuel injector for an open or for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems in the G/H Van Service Manual.

Did you complete the repair?

Go to Step 23

--

20

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

Did you complete the replacement?

Go to Step 23

--

21

Replace the FICM. Refer to Fuel Injector Control Module Replacement .

Did you complete the replacement?

Go to Step 23

--

22

Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls in the G/H Van Service Manual.

Did you complete the replacement?

Go to Step 23

--

23
  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 24

24

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