Refer to Engine Controls Schematics for electrical diagram.
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 diagnosstic trouble code (DTC).
Conditions for Running the DTC
| • | The engine speed is more than 400 RPM. |
| • | The ignition voltage is between 6 volts and 18 volts. |
Conditions for Setting the DTC
The PCM detects the wrong voltage potential on any injector driver circuit for 5 seconds.
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/DTC
| • | The PCM turns OFF the malfunction indicator lamp (MIL) 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 no failures are reported by this or any other emission related diagnostic. |
| • | Use a scan tool in order to clear the MIL and the DTC. |
Diagnostic Aids
Important: Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing or 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 and 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 Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and 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 or a fail. Operate the vehicle within the same Freeze Frame conditions such as RPM, load, vehicle speed, temperature, etc. that you observed. This will isolate when the DTC failed. For an intermittent condition, refer to Symptoms . |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step determines if a malfunction is present.
-
This step is determining if there is an intermittent condition.
-
The injector fuses also supply the ignition coils. Thoroughly inspect the circuits going to the ignition coil for a short to ground. A shorted ignition coil may also cause a fuse to open.
-
Inspect the injector connections before replacing the injector. A faulty connection causes an inoperative injector.
-
This step tests for an ignition positive voltage circuit that is shorted to ground.
-
Disconnecting the PCM allows using the DMM to measure continuity of the circuits. This aids in locating an open or shorted circuit.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||||||||
Are any of the Misfire Current Counters incrementing? | -- | |||||||||
Monitor the Misfire Hist. Counters on the Misfire Data List using a scan tool. There are a total of 8 counters. One counter per cylinder. Do any of the Misfire Hist. Counters indicate a number other than 0.0 counts? | -- | Go to Diagnostic Aids | ||||||||
Are the injector fuses OK? | -- | |||||||||
5 |
Important: Before disconnecting the injector electrical connector, refer to Fuel Injection Fuel Rail Assembly Replacement for disconnecting procedure. There is a special procedure for disconnecting the injector electrical connectors.
Does the test lamp illuminate? | -- | ||||||||
6 |
Does the injector test lamp blink? | -- | ||||||||
Did the terminal require replacement? | -- | |||||||||
Does the test lamp illuminate? | -- | |||||||||
9 | Repair the open in the injector ignition positive voltage circuit to the isolated injector. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |||||||
Is the injector driver circuit open or shorted? | -- | |||||||||
11 | Repair the injector driver circuit for an open, short to ground, or short to a voltage. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |||||||
12 | Repair the grounded ignition positive voltage circuit to the injectors. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |||||||
13 |
Did you find and correct the condition? | -- | ||||||||
14 | Replace the faulty injectors that you isolated. Refer to Fuel Injector Replacement . Is the action complete? | -- | -- | |||||||
15 |
Important:: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement . Is the action complete? | -- | -- | |||||||
16 |
Did you find and correct the condition? | -- | Go to Symptoms | |||||||
17 |
Does the scan tool indicate that this test ran and passed? | -- | ||||||||
18 | Select the Capture Info option and the Review Info option using the scan tool. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to the applicable DTC table | System OK |
