Refer to
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. When the second 3X reference pulse is recognized by the PCM, the PCM applies 5.0 volts to the Bypass circuit. The 5 volts on the Bypass circuit commands the IC Module to switch spark advance to PCM control. At this time, the IC Module will remove the ground it has applied to the IC circuit. When the IC pulses are not grounded, the IC Module can use the IC pulses to control spark advance. A short in the IC circuit or an open or short to ground in the Bypass circuit will cause the PCM to set DTC P1361. The engine may be started but will run with the ICM controlling spark timing.
Conditions for Running the DTC
| • | Engine speed greater than 600 rpm. |
| • | No DTC P1351 set. |
Conditions for Setting the DTC
| • | The PCM does not monitor IC pulses while IC mode spark advance is commanded. |
| • | 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 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 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 PCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. Refer to Intermittents and Poor Connections Diagnosis and Repairing Connector Terminals in Wiring Systems. |
| • | 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 voltmeter 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 fault. Refer to Wiring 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 | Values | Yes | No |
|---|---|---|---|---|
1 | Was the Powertrain OBD System Check performed? | -- | ||
2 |
Did DTC P1361 set? | -- | Go to Diagnostic Aids | |
3 |
Is the test lamp on? | -- | ||
4 |
Is the resistance more than the specified value? | 6Kohms (6,000ohms) | ||
5 |
Is test lamp on? | -- | ||
6 |
Was a problem found? | -- | ||
7 |
Was a problem found? | -- | ||
8 |
Is the test light on? | -- | ||
9 |
Was a problem found? | -- | ||
10 | Locate and repair short to ground in the IC circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |
11 | Locate and repair short to ground in the bypass circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |
12 |
Was a problem found? | -- | ||
13 |
Important: Replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | -- | |
14 | Replace the IC Module. Refer to Ignition Control Module Replacement . Is the action complete? | -- | -- | |
15 |
Does scan tool indicate DTC P1361 failed? | -- | System OK |
