Circuit Description
The powertrain control module (PCM) enables the appropriate fuel injector on the intake stroke for each cylinder. An ignition voltage is supplied to the fuel injectors. The PCM controls each fuel injector by grounding the control circuit via a solid state device called a driver. The PCM monitors the state of the driver. If the PCM detects an incorrect voltage for the commanded state of the driver, a fuel injector control DTC sets.
Conditions for Running the DTC
| • | The engine is running. |
| • | The ignition voltage is between 11-16 volts. |
Conditions for Setting the DTC
| • | The 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 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.
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The misfire current counters may not increment if certain DTCs are set. Use a scan tool in order to clear the DTCs. Monitoring the misfire current counters isolates which fuel injector is not operating. A misfiring cylinder may cause more than one misfire counter to increment. Diagnose the fuel injector circuit of the cylinder that displays the highest level of misfire.
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This step tests for voltage at the fuel injector harness connector. The INJR fuse supplies power to the coil side of the fuel injector harness connector. If the fuse is open, a short to ground on the fuel injector ignition voltage circuit is indicated.
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This step verifies that the PCM is able to control the fuel injector. If the test lamp blinks, then the PCM and wiring are OK.
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This step tests if a ground is constantly being applied to the fuel injector.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Controls Schematics | |||
1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | |
Are any of the misfire current counters incrementing? | Go to Step 4 | Go to Step 3 | |
3 |
Does the DTC fail this ignition? | Go to Step 4 | Go to Diagnostic Aids |
Does the test lamp illuminate? | Go to Step 5 | Go to Step 11 | |
Does the test lamp blink? | Go to Step 9 | Go to Step 6 | |
Does the test lamp remain illuminated at all times? | Go to Step 8 | Go to Step 7 | |
7 | Test the control circuit of the fuel injector for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 10 |
8 | Test the control circuit of the fuel injector 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 Step 13 |
9 | Inspect for poor connections at the harness connector of the fuel injector. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 12 |
10 | Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 13 |
11 | Repair the ignition voltage circuit of the fuel injector for an open or a short to ground. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 14 | -- |
12 | Replace the fuel injector. Refer to Fuel Injector Replacement . Is the action complete? | Go to Step 14 | -- |
13 | Replace the PCM. Refer to Powertrain Control Module Replacement . Is the action complete? | Go to Step 14 | -- |
14 |
Does the DTC run and pass? | Go to Step 15 | Go to Step 2 |
15 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | System OK | |
