The engine control module (ECM) enables the appropriate fuel injector pulse 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 control module detects an incorrect voltage for the commanded state of the driver, a diagnostic trouble code (DTC) will set.
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 |
• | The engine is running. |
• | This DTC runs continuously once the above conditions are met. |
The control module detects an open or short to ground on the fuel injector control circuit.
• | The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails. |
• | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/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 . |
• | For an intermittent condition, refer to Intermittent Conditions . |
Step | Action | Values | Yes | No |
---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connect 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 | |
2 |
Does DTC P0261, P0264, or P0267 set? | -- | Go to Step 4 | Go to Step 3 |
3 |
Did the DTC fail this ignition? | -- | Go to Step 4 | Go to Diagnostic Aids |
4 |
Does the test lamp illuminate? | -- | Go to Step 5 | Go to Step 12 |
5 |
Does the test lamp turn ON and OFF? | -- | Go to Step 7 | Go to Step 6 |
6 | Does the test lamp remain illuminated at all times? | -- | Go to Step 9 | Go to Step 8 |
7 |
Is the voltage within the specified range? | 3.4 - 4.4 V | Go to Step 10 | Go to Step 14 |
8 | Test the control circuit of the fuel injector for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 11 |
9 | 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 15 | Go to Step 11 |
10 | Test for an intermittent and for a poor connection at the fuel injector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 13 |
11 | Test for an intermittent and for a poor connection at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14 |
12 |
Did you complete the repair? | -- | Go to Step 15 | -- |
13 | Replace the affected fuel injector. Refer to Fuel Injector Replacement . Did you complete the replacement? | -- | Go to Step 15 | -- |
14 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | -- | Go to Step 15 | -- |
15 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 16 |
16 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK |