Circuit Description
The ignition system on this engine uses an individual ignition coil/module for each cylinder. The PCM controls the ignition system operation. There are eight Ignition Control (IC) circuits, one per cylinder, that connect the PCM and ignition coil/modules. Each ignition coil/module have a power feed, a chassis ground circuit and a reference low circuit. The PCM causes a spark to occur by grounding the IC circuit, which signals the ignition module to trigger the ignition coil and fire the spark plug. Sequencing and timing are PCM controlled. This DTC sets when the IC circuit is out of range.
Conditions for Setting the DTC
| • | Ignition voltage is between 9.0 volts and 17.0 volts. |
| • | The PCM detects the ignition control circuit is grounded, open or shorted to a voltage. |
| • | All conditions met for less than 1 second. |
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails. |
| • | The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Freeze Frame and/or 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
The following may be cause an intermittent:
| • | Poor connections. Check for adequate terminal tension. Refer to Repair Procedures in Electrical Diagnosis, Body and Accessories/Wiring Systems for proper procedure. |
| • | Corrosion |
| • | Mis-routed harness |
| • | Rubbed through wire insulation |
| • | Broken wire inside the insulation |
Using 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 aid in determining how many miles since the DTC set. The Fail Counter and Pass Counter can also aid determining 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
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step verifies that the fault is present.
-
This step checks the integrity of the IC circuit and the PCM output.
-
This step checks for a short to ground on the IC control circuit.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
Important: If all 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 | |
Is the frequency within the specified range? | 3.0-20 Hz | |||
Measure the voltage at the ignition control signal circuit using the DMM J 39200 . Is the voltage greater than the specified value? | 1.0 volts | |||
6 |
Does the DMM indicate continuity? | -- | ||
7 | Check the resistance from the IC circuit (at the ignition coil harness connector) to ground using the DMM J 39200 . Does the DMM indicate OL? | -- | ||
8 | Replace the ignition coil. Refer to Ignition Coil Replacement. Is the action complete? | -- | -- | |
9 | Repair the Ignition Control circuit for a short to voltage. Refer to Body and Accessories/Wiring Systems. Is the action complete? | -- | -- | |
10 | Repair the Ignition Control circuit for an open or grounded circuit. Refer to Body and Accessories/Wiring Systems. Is the action complete? | -- | -- | |
11 | Check the terminal tension at the PCM and replace the terminal if necessary. Refer to Body and Accessories/Wiring Systems. Did you find and correct the condition? | -- | ||
12 |
Important: Program the replacement PCM. Refer to Powertrain Control Module/Throttle Actuator Control Module Replacement . Replace the PCM. Is the action complete? | -- | -- | |
13 |
Does the scan tool indicate that this test ran and passed? | -- | ||
14 | 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 |
