P0320

DTC P0320 Ignition Control (IC) Error:

Ignition Control (IC) Circuit:

Circuit Description
When the system is running on the ignition control module, that is, no voltage on the bypass line, the DI module grounds the Ignition Control (IC) signal. The VCM expects to sense no voltage on the IC line during this condition. If it senses a voltage, it sets DTC P0320 and will not go into the IC mode.

When the RPM for IC is reached (about 400 RPM), and bypass voltage is applied, the IC will no longer be grounded in the DI control module so the IC voltage will vary.

DTC P0320 Will Set When
Short Test - If IC has toggled more than 0 times since the last "key-up" and VCM is commanding bypass mode. OR Long Test - If engine speed is greater than 450 RPM and IC mode is commanded.

Conditions for both tests must be detected 4 times before DTC P0320 is set.

Action Taken (VCM will default to)
VCM will disable the IC mode if the short test fails or default to bypass mode if the long test fails.

DTC P0320 Will Clear When
Conditions for fault are no longer present and Tech 1 clear DTCs function is used or 50 ignition switch keycycles have passed with no further faults or ignition switch is turned "OFF" and Fuse #9 (ECM B) fuse is removed for 10 seconds.

DTC Chart Test Description
Number(s) below refer to circled number(s) on the diagnostic chart.

1. Checks to see if DTC P0320 is intermittent.

2. Checks for a normal IC ground path through the DI module. An IC CKT 423 shorted to ground will also read less than 500 ohms; however, this will be checked later.

3. As the test light voltage touches CKT 424, the module should switch causing the ohmmeter to "over-range" if the meter is in the 100-200 ohms position.

Selecting the 10-20,000 ohms position will indicate above 5000 ohms. The important thing is that the module "switched."

4. If the module did not switch, this step checks for:
^ IC CKT 423 shorted to ground.
^ Bypass CKT 424 open.
^ Faulty ignition control module connection or module.

5. Confirms that DTC P0320 is a faulty VCM and not an intermittent in CKTs 423 or 424.

Diagnostic Aids
The Tech 1 scan tool does not have any ability to help diagnose a DTC P0320 problem. Refer to "Intermittents". - Intermittent Malfunctions