For 1990-2009 cars

### Circuit Description

The powertrain control module (PCM) enables the appropriate fuel injector on the intake stroke for each cylinder. A voltage is supplied directly 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 status of each 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 9-18 volts.

### Conditions for Setting the DTC

• | The PCM detects an incorrect voltage on the fuel injector control circuit.

• | The condition exists for 30 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 .

• | If the condition is intermittent, refer to Intermittent Conditions .

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. The misfire current counters may not increment if certain DTCs are set. Use a scan tool to clear the DTCs. Monitoring the misfire current counters isolates which fuel injector is not operating. A cylinder that is misfiring can also cause the misfire current counters to increment for another cylinder. Diagnose the cylinder with the highest level of misfire first.

2. This step isolates the condition. If the test lamp blinks, the PCM is providing ground to the fuel injector.

3. This step tests if a ground is constantly being applied to the fuel injector.

4. This step isolates the circuit between the multi-way connector and the PCM. An open or short to voltage on the fuel injector control circuit will not allow the test lamp to blink.

5. This step inspects for fuel injector harness damage between the multi-way connector and the upper intake manifold. Careful inspection may isolate the condition before removal of the upper intake manifold.

6. Perform the continuity test at the multi-way connector. If the DMM displays OL test the circuits for an open or a poor connection.

7. This step isolates the circuit between the multi-way connector and the fuel injector. A short to voltage on the fuel injector control circuit will set this DTC.

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module Connector End Views
1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls
2 |

1. Clear the DTCs with a scan tool.
2. Idle the engine at the normal operating temperature.
3. Monitor the misfire current counters with a scan tool.

Are any of the misfire current counters incrementing?

Go to Step 4

Go to Step 3

3 |

1. Observe the Freeze Frame/Failure Records for this DTC.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine.
4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text or as close to the Freeze Frame/Failure Records data that you observed.

Does the DTC fail this ignition?

Go to Step 4

Go to Diagnostic Aids

4 |

1. Turn OFF the ignition.
2. Disconnect the fuel injector harness multi-way connector.
3. Probe the appropriate fuel injector control circuit, powertrain control module (PCM) side, with a test lamp connected to B+.
4. Crank the engine.

Does the test lamp blink when cranking the engine?

Go to Step 8

Go to Step 5

5 | Does the test lamp remain illuminated at all times? | Go to Step 7 | Go to Step 6
6 | Test the control circuit of the fuel injector for a short to voltage or an open between the multi-way connector and the PCM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 18 | Go to Step 14
7 | Test the control circuit of the fuel injector for a short to ground between the multi-way connector and the PCM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 18 | Go to Step 17
8 | Inspect the accessible fuel injector jumper harness between the multi-way connector and the plenum for the following:

• | Poor connections at the multi-way connector

• | Damaged or pinched wiring

• | Broken wires inside the insulation

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 18

Go to Step 9

9 |

1. Remove the upper intake. Refer to Upper Intake Manifold Replacement in Engine Mechanical.
2. Probe the appropriate fuel injector control circuit, fuel injector side, at the multi-way connector, with a test lamp connected to B+.

Does the test lamp illuminate?

Go to Step 15

Go to Step 10

10 | With a DMM, test for continuity between the ignition voltage terminal and the appropriate fuel injector control circuit terminal, at the multi-way connector. Refer to Testing for Continuity in Wiring Systems. Does the DMM indicate OL? | Go to Step 11 | Go to Step 13
11 | Test the control circuit of the fuel injector for an open, or poor connections 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 18 | Go to Step 12
12 | Test the ignition voltage circuit of the fuel injector for an open between the fuel injector and the splice. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 18 | Go to Step 16
13 | Test the control circuit of the fuel injector for a short to voltage, or a short to another circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 18 | Go to Step 16
14 | Inspect for poor connections at the harness connector of the PCM. 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 18 | Go to Step 17
15 | Repair the short to ground in the fuel injector control circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 18 | --
16 | Replace the appropriate fuel injector. Refer to Fuel Injector Replacement . Did you complete the replacement? | Go to Step 18 | --
17 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | Go to Step 18 | --
18 |

1. Use the scan tool in order to clear the DTCs.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine.
4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC run and pass?

Go to Step 19

Go to Step 2

19 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | Go to Diagnostic Trouble Code (DTC) List | System OK