GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2002 🢒 Grand Prix 🢒 Engine 🢒 Engine Electrical 🢒 Fuel Injector Circuit Diagnosis

Circuit Description

The control module enables the appropriate fuel injector on the intake stroke for each cylinder. An individual ignition 1 voltage is supplied directly to each of the fuel injectors. The control module controls each fuel injector by grounding the control circuit via a solid state device called a driver.

Diagnostic Aids
    • Monitoring the fuel injector circuit status with a scan tool while moving the fuel injector harness may help to isolate an intermittent condition.
    • 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 ignition 1 voltage supply circuit of the fuel injector.

    2.

  2. This step tests for a short to ground on the ignition 1 voltage supply circuit of the fuel injector.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

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

Are any fuel injector DTCs set?

--

Go to DTC P0201, P0202, P0203, P0204, P0205, or P0206

Go to Step 3

3

Inspect the fuel injector fuse.

Is the fuel injector fuse open?

--

Go to Step 4

Go to DTC P0341

4

  1. Turn OFF the ignition.
  2. Disconnect a fuel injector electrical connector.
  3. Probe the ignition 1 voltage supply circuit of the fuel injector with a test lamp connected to B+.

Does the test lamp illuminate?

--

Go to Step 5

Go to Step 6

5

Test the ignition 1 voltage supply circuit of the fuel injector, between the fuel injector fuse and 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 7

Go to Diagnostic Aids

6

Inspect for poor connections at the harness connector of the fuel injectors. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 7

Go to Diagnostic Aids

7

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3