GM Service Manual Online
For 1990-2009 cars only

Refer to Engine Controls Schematics

CKP, CMP, ICM, Bank 1 KS and Bank 2 KS


Object Number: 588115  Size: FS
Underhood Accessory Wiring Junction Block, ICM, Automatic Transaxle, Stop Lamp Switch and EBCM
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice
Engine Controls Components
Powertrain Control Module Description
Fuel Tank
Power, Ground, MIL and Data Link
OBD II Symbol Description Notice
for a wiring diagram.

Circuit Description

The Ignition Control Module (ICM) sends signals that the PCM requires for fuel control and spark advance calculations. At the start of engine crank, the ICM controls the spark advance. When the PCM recognizes the second 3X reference pulse is recognized, the PCM applies 5 volts to the Bypass circuit, commanding the ICM to switch spark advance to PCM control. If the PCM detects an open in the Bypass circuit, the engine will start and may run in Bypass mode timing. DTC P1352 will set.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

The PCM detects an open circuit in the Bypass circuit.

Action Taken When the DTC Sets

    • The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.
    • The PCM will store conditions which were present when the DTC set as Freeze Frame/Failure Records data.

Conditions for Clearing the MIL/DTC

    • The PCM will turn OFF the malfunction indicator lamp (MIL) during the third consecutive trip in which the diagnostic has run and passed.
    • The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
    • The DTC can be cleared by using a scan tool.

Diagnostic Aids

Inspect for the following conditions.

Many situations may lead to an intermittent condition. Perform each inspection or test as directed.

Important: :  Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.

    • Loose terminal connection
       -  Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair.
       -  Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair.
    • Damaged harness--Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair.
    •  Inspect the powertrain control module (PCM) and the engine grounds for clean and secure connections. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair.

If the condition is determined to be intermittent, reviewing the Snapshot or Freeze Frame/Failure Records may be useful in determining when the DTC or condition was identified.

Test Description

The numbers below refer to the step numbers on the Diagnostic Table:

  1. This vehicle is equipped with a PCM which uses an electrically erasable programmable read-only memory (EEPROM). When you replace the PCM, you must program the new PCM.

DTC P1352 - Bypass Circuit Open

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 OFF the ignition.
  2. Disconnect the PCM.
  3. Connect the DMM between the IC and the Reference Low Circuits at the PCM connector.
  4. Turn ON the ignition.
  5. Probe the BYPASS circuit with a test lamp connected to B+.

Is the DMM voltage within the specified range?

150 mV to 250 mV

Go to Step 4

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Leave the PCM disconnected.
  3. Disconnect the Ignition Control Module connector.
  4. Check for an open in the BYPASS circuit.
  5. If you find a problem, repair the condition as necessary. Refer to Wiring Repairs in Wiring Systems .

Did you find a problem?

--

Go to Step 8

Go to Step 5

4

  1. Check for faulty terminal connections at the PCM.
  2. If you find a problem, repair the condition as necessary. Refer to Testing for Continuity , refer to Repairing Connector Terminals and refer to Connector Repairs in Wiring Systems.

Did you find a problem?

--

Go to Step 8

Go to Step 7

5

  1. Check for faulty terminal connections at the Ignition Control Module.
  2. If you find a problem, repair the condition as necessary. Refer to Testing for Continuity , refer to Repairing Connector Terminals and refer to Connector Repairs in Wiring Systems.

Did you find a problem?

--

Go to Step 8

Go to Step 6

6

Replace the Ignition Control Module. Refer to Ignition Control Module Replacement .

Is the action complete?

--

Go to Step 8

--

7

Important: You must program the replacement PCM.

Replace the PCM.

Refer to Powertrain Control Module Replacement/Programming .

Is the action complete?

--

Go to Step 8

--

8

  1. Review and record the scan tool Fail Records data.
  2. Clear the DTCs.
  3. Operate the vehicle within the Fail Records conditions.
  4. Use the scan tool in order to monitor the Specific DTC Info for DTC P1352.

Does the scan tool indicate that DTC P1352 failed this ignition?

--

Go to Step 2

System OK