GM Service Manual Online
For 1990-2009 cars only

Circuit Description

There are two separate ignition module assemblies, one for each bank of cylinders. Each assembly contains an ignition control (IC) module and four coils. Each IC module consists of the following circuits:

    • An ignition 1 voltage
    • A ground
    • An IC timing low reference
    • IC circuits for cylinders 1-8

Each ignition coil connects directly to its spark plug via a short boot. The IC circuits transmit timing pulses from the powertrain control module (PCM) to the IC modules, which triggers the coils to fire the plugs in the correct sequence. The PCM monitors each IC circuit for improper voltage levels.

If a short to ground occurs in one of the CI circuits, DTC P0351-P0358 sets.

Conditions for Running the DTC

The engine speed is more than 400 RPM.

Conditions for Setting the DTC

The PCM detects a short to ground on the IC circuit for less than 1 second.

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.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls 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. Start the engine.
  2. Observe the Misfire Counters parameter with a scan tool.

Does the scan tool Misfire Counters increment for the affected cylinder?

Go to Step 3

Go to Intermittent Conditions

3

  1. Turn OFF the ignition.
  2. Disconnect the ignition coil (IC) module assembly associated with the affected cylinder.
  3. Probe the affected IC control circuit in the harness connector with a test lamp that is connected to battery voltage.

Does the test lamp illuminate?

Go to Step 4

Go to Step 5

4

  1. Disconnect the powertrain control module (PCM).
  2. Probe the affected IC circuit at the harness connector with a test lamp that is connected to battery voltage.

Does the test lamp illuminate?

Go to Step 7

Go to Step 9

5

Test for an intermittent and for a poor connection at the IC module. 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 10

Go to Step 8

6

Test for an intermittent and for a poor connection a 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 10

Go to Step 9

7

Repair the short to ground in the affected IC control circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 10

--

8

Replace the IC module. Refer to Ignition Coil Replacement - Bank 1 or Ignition Coil Replacement - Bank 2 .

Did you complete the replacement?

Go to Step 10

--

9

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

Go to Step 10

--

10

  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 2

Go to Step 11

11

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK