Refer to Engine Controls Schematics for wiring view.
Circuit Description
The ignition control module (ICM) determines crankshaft and camshaft position and fires the appropriate spark plug. The ICM also creates 4X and 24X reference pulses that are supplied to the powertrain control module (PCM). The PCM uses these reference circuits to determine fuel delivery and spark timing. Most failures in the ignition control system will set a PCM diagnostic trouble code (DTC). Always perform the Powertrain On Board Diagnostic (OBD) System Check and, if necessary, the Engine Cranks but Does Not Run diagnostic table BEFORE performing any ignition system diagnsosis.
Test Description
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The Engine Cranks but Does Not Run table must be performed BEFORE using this diagnostic procedure.
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Observe the Engine Speed parameter on the scan tool while increasing spark RETARD by 10 degrees. The PCM will attempt to keep the engine speed at the Desired Idle during spark retard by slightly increasing spark advance. The engine speed may initially drop by 50 RPM then increase slightly to average 30 RPM less than the RPM observed during normal spark control.
If engine speed fails to decrease, proceed to step 4 of DTC P1350 diagnosis.
Step | Action | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | |||||||||
2 | Using a scan tool, check for stored PCM diagnostic trouble codes. Are any DTCs set? | -- | Go to the DTCs | Go to Step 3 | ||||||||
Attempt to start and idle the engine. Does the engine start? | -- | Go to Step 4 | Go to Step 7 | |||||||||
Does engine speed decrease as spark is retarded? | -- | Go to Step 5 | ||||||||||
5 |
Is a miss, stumble, or hesitation observed? | -- | Go to Step 6 | |||||||||
6 | Were any other driveability symptoms observed? | -- | Go to Symptoms | System OK | ||||||||
7 |
Does the test lamp illuminate? | -- | Go to Step 11 | Go to Step 8 | ||||||||
8 | Connect the test lamp between terminal C and a good engine ground. Does the test lamp illuminate? | -- | Go to Step 9 | Go to Step 10 | ||||||||
9 | Repair the open ground circuit to the IC module. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 12 | -- | ||||||||
10 | Repair the cause of no voltage to the ICM. Possibilities include the following:
Is the repair complete? | -- | Go to Step 12 | -- | ||||||||
11 |
Was terminal contact repaired? | -- | Go to Step 12 | Go to Ignition System CKP Sensor Diagnosis | ||||||||
12 | Select the Capture Info option and Review Info option using the scan tool. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to the applicable DTC table | System OK |
