GM Service Manual Online
For 1990-2009 cars only

Object Number: 626200  Size: LF
Engine Controls Components
Ignition Control Module
OBD II Symbol Description Notice
Powertrain Control Module Connector End Views
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The powertrain control module (PCM) checks for CAM pulses being received without 4X reference pulses.

Conditions for Running the DTC

    •  DTC P0340 is not set.
    • The engine speed is above 496 RPM.
    • The ignition voltage is above 6 volts.
    •  A CAM sensor signal has been received in the last 4 seconds.

Conditions for Setting the DTC

No 4X reference pulses received for 4 seconds.

Action Taken When the DTC Sets

PCM uses 24X signal for ignition and fuel control.

    •  The malfunction indicator lamp (MIL) will not illuminate.
    •  The PCM will command a message to be displayed.
    •  The PCM records the operating conditions at the time the diagnostic fails. This information will be stored in the Failure Records.

Conditions for Clearing the Message/DTC

    •  The PCM will turn the message OFF after one run and pass of the diagnostic test.
    •  A History DTC will clear after forty consecutive warm-up cycles with no failures of any non-emission related diagnostic test.
    •  A last test failed, or current DTC, will clear when the diagnostic runs and does not fail.
    • Use a scan tool in order to clear DTCs.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Using Freeze Frame and Failure Records may help locate an intermittent condition. Operate the vehicle within the same conditions that you observed in the Freeze Frame and Failure Records.

  2. This step is testing the ignition control module (ICM) 4X signal circuit for a short to voltage.

  3. This step is testing the continuity of the 4X signal circuit. If the DMM displays OL, an open circuit, or poor PCM connection is indicated.

  4. This step is testing the 4X signal circuit and the PCM. If the resistance value displayed on the DMM changes as the ignition is turned OFF, then the 4X signal circuit and the PCM are OK.

  5. This step is testing the ground circuit for the ICM. An open ground circuit can cause a variety of ignition control concerns.

DTC P0322

Step

Action

Value(s)

Yes

No

1

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

  1. Turn ON the ignition, with the engine OFF.
  2. Review the Freeze Frame and/or Failure Records data for this DTC and observe the parameters.
  3. Turn OFF the ignition for 15 seconds.
  4. Attempt to start and idle the engine.
  5. Monitor the diagnostic trouble code (DTC) information with a scan tool.

Does the scan tool indicate that this diagnostic failed this ignition?

--

Go toStep 3

Go to Diagnostic Aids

3

  1. Turn OFF the ignition.
  2. Disconnect the ICM connector C4.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the 4X signal circuit, at the ICM connector C4, with the DMM connected to battery ground. Refer to Measuring Voltage in Wiring Systems.

Is the voltage the less than the value specified?

0.5 volts

Go to Step 4

Go to Step 11

4

Measure the continuity of the 4X signal circuit with the DMM connected to battery ground. Refer to Testing for Continuity in Wiring Systems.

Does the DMM display OL?

--

Go to Step 8

Go to Step 5

5

  1. Turn OFF the ignition.
  2. Monitor the DMM.

Does the resistance value change when the ignition is turned OFF.

--

Go to Step 6

Go to Step 8

6

  1. Disconnect the ICM connector C2.
  2. Test the continuity of the ICM ground circuit with the DMM. Refer to Testing for Continuity in Wiring Systems.

Does the DMM display continuity?

--

Go to Step 7

Go to Step 10

7

  1. Inspect for poor connections at the ICM. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.
  2. If you find a poor connection, repair the condition as necessary. Refer to Repairing Connector Terminals in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 12

8

  1. Turn OFF the ignition.
  2. Disconnect the PCM connector C1, located on the same side as the manufacturers logo.
  3. Test the 4X signal circuit for an open or a short to ground. Refer to Testing for Continuity in Wiring Systems.
  4. If you find the 4X signal circuit open or shorted to ground, repair the condition as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 9

9

  1. Inspect for poor connections at the PCM. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.
  2. If you find a poor connection, repair the condition as necessary. Refer to Repairing Connector Terminals in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 13

10

Repair the ICM ground circuit for an open. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 14

--

11

Repair the ICM 4X circuit for a short to voltage. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 14

--

12

Replace the ICM. Refer to Ignition Control Module Replacement .

Is the action complete?

--

Go to Step 14

--

13

Important: The replacement PCM must programmed.

Replace the PCM. Refer to Powertrain Control Module Replacement/Programming .

Is the action complete?

--

Go to Step 14

--

14

  1. Select the Diagnostic Trouble Code (DTC) option and the Clear DTC option with the scan tool.
  2. Idle the engine at the normal operating temperature.
  3. Select the Diagnostic Trouble Code (DTC) option and the specific DTC option, then enter the DTC number with the scan tool.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text, if applicable.

Does the scan tool indicate that this test ran and passed?

--

Go to Step 15

Go to Step 3

15

Select the Capture Info option and the Review Info option with the scan tool.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to the applicable DTC table

System OK