Circuit Description
The ignition system on this engine uses an individual ignition coil for each cylinder. The powertrain control module (PCM) controls the ignition system operation. The PCM controls each coil using one of eight ignition control (IC) circuits. The PCM commands the IC circuit low when a spark event is requested. This causes the IC module to energize the ignition coil to create a spark at the spark plug. Each ignition coil has the following circuits:
| • | An igntion positive voltage circuit |
| • | A ground circuit |
| • | An ignition control (IC) circuit |
| • | A reference low circuit |
Sequencing and timing are PCM controlled. This diagnostic trouble code (DTC) sets when the IC circuit is out of range.
Conditions for Running the DTC
| • | The engine is running. |
| • | Ignition voltage is between 9 volts and 17 volts. |
Conditions for Setting the DTC
| • | The PCM detects the ignition control circuit is grounded, open, or shorted to a voltage. |
| • | All conditions are met for less than 1 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/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 |
Using 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 aid in determining how many miles since the DTC set. The Fail Counter and Pass Counter can also aid in determining 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 verifies that the fault is present.
-
This step tests for a short to ground on the IC control signal circuit.
-
This step tests the integrity of the IC circuit and the PCM output.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
Important: If all of the ignition control (IC) DTCs are set at the same time, inspect the IC ground circuits for an open. Does the scan tool indicate Fault? | -- | |||
3 |
Does the scan tool indicate that this diagnostic failed this ignition? | -- | Go to Diagnostic Aids | |
4 |
Is the voltage more than the specified value? | 1.0 volts | ||
Does the DMM indicate continuity? | -- | |||
6 | Test the resistance from the IC circuit to ground using the DMM . Does the DMM indicate OL? | -- | ||
7 |
Is the test lamp illuminated? | -- | ||
8 | Connect a test lamp between the ignition coil Ignition positive voltage circuit and the ignition coil ground circuit. Is the test lamp illuminated? | -- | ||
9 | Repair the ignition control circuit for a short to voltage. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | ||
10 | Repair the ignition coil Control circuit for an open or short to ground. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |
Is the frequency within the specified range? | 3.0-20 Hz | |||
12 | Replace the ignition coil. Refer to Ignition Coil Replacement . Is the action complete? | -- | -- | |
13 |
Did you find and correct the condition? | -- | ||
14 |
Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement Replace the PCM. Is the action complete? | -- | -- | |
15 |
Does the scan tool indicate that this test ran and passed? | -- | ||
16 | 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 |
