Circuit Description
The control module enables the appropriate fuel injector on the intake stroke for each cylinder. Ignition voltage is supplied directly to the fuel injectors. The control module controls each fuel injector by grounding the control circuit with a solid state device called a driver. The control module monitors the status of each driver. Each driver has a feedback voltage circuit which the engine control module (ECM) monitors. The injector control circuits are pulled-up to voltage within the ECM . The ECM can determine if a control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage. If the ECM detects the control circuit voltage is too low when the circuit is commanded OFF, this DTC sets.
DTC Descriptors
This diagnostic procedure supports the following DTCs.
| • | DTC P0261 Injector 1 Control Circuit Low Voltage |
| • | DTC P0264 Injector 2 Control Circuit Low Voltage |
| • | DTC P0267 Injector 3 Control Circuit Low Voltage |
| • | DTC P0270 Injector 4 Control Circuit Low Voltage |
| • | DTC P0273 Injector 5 Control Circuit Low Voltage |
| • | DTC P0276 Injector 6 Control Circuit Low Voltage |
Conditions for Running the DTC
| • | The engine speed is more than 80 RPM. |
| • | The ignition 1 voltage is between 10-18 volts. |
| • | DTCs P0261, P0264, P0267, P0270, P0273, and P0276 run continuously once the above conditions are met . |
Conditions for Setting the DTC
| • | The ECM detects a grounded fuel injector circuit. |
| • | The condition exists for more than 1 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 4 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
The following table illustrates the ECM connector locations:
ECM Connector Location | |
|---|---|
C2 | C1 |
Front of Vehicle | |
| • | Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector. |
| • | Performing the fuel injector coil test may help isolate an intermittent condition. Refer to Fuel Injector Solenoid Coil Test . |
| • | If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the circuit status for the component with a scan tool. The circuit status parameter changes from OK or Indeterminate to Fault if there is a condition with the circuit or a connection. The ODM information is in the output driver module (ODM) data list. |
| • | If the condition is intermittent, refer to Intermittent Conditions . |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step determines if the condition is current.
-
This step determines if the ignition 1 voltage supply circuit is shorted to ground. The fuel injectors for each bank of the engine are fused separately. If the circuit is shorted to ground, all the injector low voltage DTCs will set for one bank of the engine.
-
This step isolates if the short to ground condition is on the injector side of the multi-way harness connector or the ECM side of the multi-way harness connector. If a low voltage DTC sets, the short to ground condition is between the multi-way harness connector and the ECM.
-
This step isolates the condition. If the test lamp illuminates the injector control circuit is shorted to ground between the multi-way harness connector and the fuel injectors.
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 | |
Is DTC P0261, P0264, P0267, P0270, P0273, or P0276 set? | Go to Step 3 | Go to Step 4 | |
Are DTCs P0261, P0267, and P0273 set at the same time, or are DTCs P0264, P0270, and P0276 set at the same time? | Go to Step 7 | Go to Step 5 | |
4 |
Did the DTC fail this ignition? | Go to Step 4 | Go to Diagnostic Aids |
Important: Disconnecting the multi-way harness connector causes P0201-P0206 fuel injector circuit open DTCs to set. Is DTC P0261, P0264, P0267, P0270, P0273, or P0276 set? | Go to Step 6 | Go to Step 10 | |
6 | Test the control circuit of the appropriate fuel injector for a short to ground between the multi-way connector and the engine control module (ECM). Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 11 |
Does the test lamp illuminate? | Go to Step 8 | Go to Step 9 | |
8 |
Did you complete the repair? | Go to Step 12 | -- |
9 |
Did you complete the repair? | Go to Step 12 | -- |
10 |
Did you complete the repair? | Go to Step 12 | -- |
11 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | Go to Step 12 | -- |
12 |
Did the DTC fail this ignition? | Go to Step 2 | Go to Step 13 |
13 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | System OK | |
