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For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 Safari - 4WD 🢒 Engine 🢒 Engine Controls - 4.3L 🢒 Fuel Injector Circuit Diagnosis

Circuit Description

The powertrain control module (PCM) enables the appropriate fuel injector on the intake stroke 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.

Diagnostic Aids
    • Performing the Fuel Injector Coil Test may help 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. This step tests for a short to ground on the fuel injector B+ supply circuit.

    2.

  2. This step tests for a short to a PCM ground on the fuel injector B+ supply circuit.

    3.

  3. This step tests for an open ignition feed circuit between the fuel pump relay and the fuel injectors.

    4.

  4. This step tests for high resistance between the fuel pump relay and the fuel injectors.

Step

Action

Values

Yes

No

Schematic Reference:

Fuel Injection Controls


Object Number: 655204 Size: FS
Master Electrical Component List
Fuel System Description
Fuel Mixture Input Controls
Fuel Delivery
OBD II Symbol Description Notice
ING-A Fuse and Ignition Switch
ECM-1 Fuse

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to  Step 2

Go to Diagnostic System Check - Engine Controls

2

Is DTC P0200 set?

--

Go to DTC P0200

Go to  Step 3

3

Inspect the ECM 1 fuse.

Is the ECM 1 fuse open?

--

Go to  Step 4

Go to  Step 6

4

  1. Turn OFF the ignition.
  2. Remove the engine cover. Refer to Engine Cover Replacement in Interior Trim.
  3. Disconnect the harness connector of the fuel injectors.
  4. Probe the ignition voltage circuit of a fuel injector, fuse side, with a test lamp connected to B+.

Is the test lamp illuminated?

--

Go to  Step 8

Go to  Step 5

5

Turn ON the ignition, with the engine OFF.

Is the test lamp illuminated?

--

Go to  Step 11

Go to Diagnostic Aids

6

  1. Turn OFF the ignition.
  2. Remove the engine cover. Refer to Engine Cover Replacement in Interior Trim.
  3. Disconnect the harness connector of the fuel injectors.
  4. Turn ON the ignition, with the engine OFF.
  5. Probe the ignition voltage circuit of the fuel injector, fuse side, with a test lamp connected to a good ground.

Is the test lamp illuminated?

--

Go to  Step 7

Go to  Step 9

7

Test for continuity between the ECM 1 fuse and an ignition feed terminal of a fuel injector. Refer to Testing for Continuity in Wiring Systems.

Does the DMM display a resistance above the specified value?

5 ohms

Go to  Step 10

Go to Intermittent Conditions

8

Test the ignition voltage circuit of the fuel injectors for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to  Step 12

--

9

Repair the open in the ignition voltage circuit of the fuel injectors. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to  Step 12

--

10

Repair the high resistance in the ignition voltage circuit of the fuel injectors. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to  Step 12

--

11

Repair the short to a PCM ground in the ignition voltage circuit of the fuel injectors. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to  Step 12

--

12

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to  Step 3