Refer to Engine Controls Schematics .
Circuit Description
The powertrain control module (PCM) enables an injector on the intake stroke of each cylinder. Individual cylinder fuel control is referred to as sequential multi-port fuel injection (SFI).
Ignition voltage is supplied directly to the fuel injectors. The PCM controls each injector by grounding the control circuit via an internal switch called a driver. The primary function of the driver is to supply the ground for the component being controlled. Each driver or control circuit is equipped with a fault line which is monitored by the PCM. When the PCM is commanding an injector ON, the voltage of the control circuit should be low. When the PCM is commanding the injector OFF, the voltage potential of the control circuit should be high. If the PCM detects the injector control circuit voltage other than what is expected, the PCM sets a DTC.
Conditions for Running the DTC
| • | The engine is running. |
| • | The ignition voltage is more than 9.0 volts. |
Conditions for Setting the DTC
The PCM detects an injector current less than 4 amps for one second.
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL or DTC
| • | The PCM turns the malfunction indicator lamp (MIL) OFF after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A last test failed, or current DTC, clears when the diagnostic runs and does not fail. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures. |
| • | Use a scan tool in order to clear the MIL or DTC. |
Diagnostic Aids
Important: Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing/replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM.
| • | The following may cause an intermittent: |
| - | Poor connections--Check for adequate terminal tension. Refer to Testing for Intermittent Conditions and Poor Connections or to Connector Repairs in Wiring Systems. |
| - | Corrosion |
| - | Mis-routed harness |
| - | Rubbed through wire insulation |
| - | Broken wire inside the insulation |
| • | When the injector driver is disabled, an engine misfire will be apparent and a misfire DTC sets. |
| • | Using the Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can also help determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate the vehicle within the same Freeze Frame conditions (RPM, load, vehicle speed, temperature etc.) that you observed. This will isolate when the DTC failed. For an intermittent condition, refer to Symptoms . |
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | |
2 |
Is the misfire counter incrementing? | -- | Go to Step 4 | Go to Step 3 |
3 |
Did the DTC set again? | -- | Go to Step 4 | Go to Diagnostic Aids |
4 |
Is the resistance near the specification? | 11.0-15.0 ohms | Go to Step 5 | Go to Step 9 |
5 |
Is the test lamp illuminated? | -- | Go to Step 15 | Go to Step 6 |
6 |
Is the test lamp illuminated? | -- | Go to Step 15 | Go to Step 7 |
7 |
Is the test lamp illuminated? | -- | Go to Step 8 | Go to Step 16 |
8 |
Is the resistance within the specification? | 0-0.5 ohms | Go to Step 17 | Go to Step 14 |
9 |
Is the resistance within the specification? | 0-0.5 ohms | Go to Step 10 | Go to Step 14 |
10 | Probe the injector B+ circuit between the 5-way connector and the injector connector using a DMM set to ohm scale. Is the resistance within the specification? | 0-0.5 ohms | Go to Step 11 | Go to Step 16 |
11 | Check for loose or spread terminals at the injector connector. Repair as necessary. Refer to Connector Repairs in Wiring Systems. Was a condition found? | -- | Go to Step 20 | Go to Step 12 |
12 |
Is the test lamp illuminated? | -- | Go to Step 18 | Go to Step 13 |
13 | Replace the injector. Refer to Fuel Injector Replacement . Is the action complete? | -- | Go to Step 20 | -- |
14 | Repair the open injector control circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 20 | -- |
15 | Repair the short to ground in the injector control circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 20 | -- |
16 | Repair the open B+ circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 20 | -- |
17 | Check for loose terminals, poor connection and proper pin fit at the PCM connector and repair as necessary. Refer to Connector Repairs in Wiring Systems. Was a condition found? | -- | Go to Step 20 | Go to Step 19 |
18 | Repair the short to voltage on the injector control circuit. Refer to Connector Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 20 | -- |
19 |
Important: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | Go to Step 20 | -- |
20 |
Does the scan tool indicate that this diagnostic Ran and Passed? | -- | Go to Step 21 | Go to Step 2 |
21 | Does the scan tool display any additional undiagnosed DTCs? | -- | Go to applicable DTC table | System OK |
