For 1990-2009 cars

### 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

• | Monitoring the fuel injector circuit status with a scan tool, while moving the fuel injector harness, may help 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. This step tests for a short to a PCM ground on the ignition 1 voltage supply circuit of the fuel injector.

3. This step tests for an open between the multi-way connector and the fuel injectors.

4. This step tests for an open or high resistance between the multi-way connector and the fuel injectors.

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 Step 6
4 |

1. Turn OFF the ignition.
2. Disconnect the multi-way harness connector of the fuel injectors.
3. Probe the ignition 1 voltage circuit of the fuel injector, fuse side, with a test lamp connected to B+.

Does the test lamp illuminate?

--

Go to Step 9

Go to Step 5

5 | Turn ON the ignition, with the engine OFF. Does the test lamp illuminate? | -- | Go to Step 13 | Go to Step 8
6 |

1. Turn OFF the ignition.
2. Disconnect the multi-way harness connector of the fuel injectors.
3. Turn ON the ignition, with the engine OFF.
4. Probe the ignition 1 voltage circuit of the fuel injector, fuse side, with a test lamp connected to a good ground.

Does the test lamp illuminate?

--

Go to Step 7

Go to Step 10

7 | Test for continuity between the ignition voltage terminal and a fuel injector terminal, at the multi-way harness connector, fuel injector side. Refer to Testing for Continuity in Wiring Systems. Does the DMM display a resistance above the specified value? | 5 ohms | Go to Step 11 | Go to Step 12
8 | Test the ignition 1 voltage circuit of the fuel injector, between the multi-way harness connector 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 14 | Go to Intermittent Conditions
9 | Repair the short to ground in the ignition voltage circuit of the fuel injector. Refer to Circuit Testing in Wiring Systems. Did you complete the repair? | -- | Go to Step 14 | --
10 | Repair the open in the ignition 1 voltage between UBEC and the multi-way connector. Refer to Circuit Testing in Wiring Systems. Did you complete the repair? | -- | Go to Step 14 | --
11 | Repair the ignition 1 voltage circuit of the fuel injectors for an open and/or high resistance, between the multi-way connector and the splice. Refer to Circuit Testing in Wiring Systems. Did you complete the repair? | -- | Go to Step 14 | --
12 | Repair the poor connection at the multi-way connector. Refer to Connector Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 14 | --
13 | Repair the short to a PCM ground in the ignition voltage circuit of the fuel injector. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 14 | --
14 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 3