The engine control module (ECM) enables the appropriate fuel injector on the intake stroke for each cylinder. Ignition voltage is supplied to the fuel injectors. The ECM controls each fuel injector by grounding the control circuit via a solid state device called a driver. The ECM monitors the status of each driver. If the ECM detects an incorrect voltage for the commanded state of the driver, a fuel injector control DTC sets.
• | The engine speed is more than 40 RPM. |
• | The system voltage is between 7.5-15 volts. |
• | The ECM detects low voltage condition on the fuel injector control circuit. |
• | The condition exists for 30 seconds. |
• | 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. |
• | 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. |
• | Performing the Fuel Injector Coil Test may help isolate an intermittent condition. Refer to Fuel Injector Solenoid Coil Test . |
• | If the condition is intermittent, refer to Intermittent Conditions . |
The numbers below refer to the step numbers on the diagnostic table.
This step verifies that the condition is present.
This step isolates the condition. If the test lamp is illuminated the injector control circuit is shorted to ground between the multi-way connector and the ECM.
This step tests for a short to ground in the fuel injector control circuit between the multi-way connector and the appropriate fuel injector.
This step isolates the circuit between the multi-way connector and the ECM.
This step inspects for fuel injector harness damage between the multi-way connector and the intake plenum. Careful inspection may isolate the condition before removal of the intake plenum.
Step | Action | Yes | No | ||||||
---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views | |||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | |||||||
Important: If DTCs P0261, P0264, P0267, P0270, P0273, or P0276 are all set, inspect the ignition 1 voltage supply circuit for and open between the underhood bussed electrical center (UBEC) and the splice.
Does an injector DTC set? | 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 6 | Go to Step 5 | |||||||
With the test lamp still connected to B+, probe the appropriate fuel injector control circuit, fuel injector harness side. Does the test lamp illuminate? | Go to Step 7 | Go to Intermittent Conditions | |||||||
Test the control circuit of the fuel injector for a short to ground between the multi-way connector and the ECM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 10 | |||||||
Did you find and correct the condition? | Go to Step 13 | Go to Step 8 | |||||||
8 |
Did you find and correct the condition? | Go to Step 13 | Go to Step 9 | ||||||
9 | Inspect for poor connections at the harness connector of the appropriate fuel injector harness connector. 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 13 | Go to Step 11 | ||||||
10 | Inspect for poor connections at the harness connector of the ECM. 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 13 | Go to Step 12 | ||||||
11 | Replace the appropriate fuel injector. Refer to Fuel Injector Replacement and Fuel Injector and Fuel Rail Replacement . Did you complete the replacement? | Go to Step 13 | -- | ||||||
12 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | Go to Step 13 | -- | ||||||
13 |
Did the DTC fail this ignition? | Go to Step 2 | Go to Step 14 | ||||||
14 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | System OK |