Refer to Engine Controls Schematics
Cell 21: Ignition Controls
.
Circuit Description
The Ignition Control (IC) Module sends signals that the PCM requires for fuel control and spark advance calculations. At the start of engine crank, the IC Module controls spark advance (Bypass mode.) When the second 3X reference pulse is recognized by the PCM, the PCM applies 5 volts to the Bypass circuit, commanding the IC Module to switch spark advance to PCM control (IC mode). If the PCM detects an open in the Bypass circuit, DTC P1352 will set. The engine will start and may run in Bypass mode timing.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
| • | The PCM detects an open circuit in the Bypass circuit. |
| • | The conditions is present for 300 3X reference periods (100 crankshaft revolutions). |
Action Taken When the DTC Sets
| • | The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecuitive trip in which the diagnostic has been run and failed. |
| • | If equipped with traction control, the PCM will command the EBTCM via the serial data circuit to turn OFF traction control, and the EBTCM will illuminate the TRACTION OFF lamp. |
| • | The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic has been 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 the scan tool. |
Diagnostic Aids
Check for the following conditions:
| • | Poor connection at the PCM. |
| Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. |
| • | Damaged harness. |
| Inspect the wiring harness for damage. If the harness appears to be OK, disconnect the IC Module, turn the ignition on and observe a digital multimeter connected between the IC circuit and battery positive voltage while moving connectors and wiring harnesses related to the IC Module. A change in voltage will indicate the location of the malfunction. |
Refer to Testing for Continuity , Intermittents and Poor Connections Diagnosis , Repairing Connector Terminals , and Connector Repairs in Wiring Systems.
Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Powertrain OBD System Check performed? | -- | ||
2 |
Does the J 39200 DMM display a resistance above the specified value? | 5,000ohms | ||
3 |
Was a problem found? | -- | ||
4 |
Was a problem found? | -- | ||
5 |
Was a problem found? | -- | ||
6 | Replace the Ignition Control Module. Refer to Ignition Coil(s) Replacement . Is the action complete? | -- | -- | |
7 |
Important: : Replacement PCM must be reprogrammed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Is the action complete? | -- | -- | |
8 |
Does the scan tool indicate DTC 1352 failed this ignition? | -- | System OK |
