P0204

P0204-FUEL INJECTOR 4 CIRCUIT/OPEN

For complete wiring diagrams refer to Diagrams/Electrical.


Theory of Operation

The ECM actuates the solenoid causing the needle valve to rise and fuel flows through the spray holes in the nozzle tip into the combustion chamber. The MIL lamp will light immediately after the diagnostic runs and fails. During this time the customer may experience engine surge or stumble. The MIL lamp will turn off once the diagnostic runs and passes in 4 consecutive drive cycles.

- When Monitored:

While the engine is running.

- Set Condition:

When the injector current falls below a calibrated threshold.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test


1. OTHER DTC'S

With the scan tool, read DTCs.

Are all 6 of the injector DTC's (P0201 - P0206) present?

Yes

- Go To 2

No

- Go To 3

2. PASS TROUGH CONNECTORS OPEN

Inspect wiring harness for signs of multiple open circuits between the ECM and the injector pass through connectors. Inspect the wiring harness between the pass through connectors to the injectors.

Are there open circuits in the wiring harness?

Yes

- Repair or replace the open connectors or wiring.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 3

3. FUEL INJECTOR

Turn the ignition off.

Disconnect the pigtail nuts from the suspect injector. Measure the resistance between the solenoid posts of the injector.


NOTE: Be sure to zero the ohm meter prior to checking the injector circuit.

Is the resistance less than 1 ohm and greater than 0 ohms?

Yes

- Go To 4

No

- Replace the fuel injector.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

4. INJECTOR HARNESS OPEN





Connect the pigtail nuts for the suspect injector.

Disconnect the injector harness connector for the suspect injector.


NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance of the injector harness circuit between the high side driver circuit and the low side driver circuit for the suspect injector at the injector harness connector.


NOTE: Be sure to zero the ohm meter prior to checking the injector circuit.

Is the resistance less than 1 ohm and greater than 0 ohms?

Yes

- Go To 5

No

- Replace or repair the injector harness.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

5. HIGH SIDE DRIVER HARNESS OPEN





Disconnect the ECM harness connectors.


NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance of the high side driver circuit between the ECM connector and the injector harness connector.

Is the resistance less than 10 Ohms?

Yes

- Go To 6

No

- Replace or repair the open engine harness.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

6. LOW SIDE DRIVER HARNESS OPEN





Measure the resistance of the low side driver circuit between the ECM connector and the injector harness connector.

Is the resistance less than 10 Ohms?

Yes

- Test Complete.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Replace or repair the open engine harness.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test