Displaying & Reading Trouble Codes

HOW TO ENTER DIAGNOSTIC MODE

To enter diagnostic mode, proceed as follows:

1. Turn ignition ON.

2. Depress the OFF and WARMER buttons on the ECC Head simultaneously and hold until all display panel segments illuminate which indicates the beginning of the diagnostic readout, Figure 4.

The purpose of illuminating the Climate Control Head is to check that all segments of the displays are working. Diagnosis should not be attempted unless all segments appear as this could lead to misdiagnosis (Code 31 could be code 34 with two segments of the display inoperative, etc.). If any of the segments are inoperative, the affected display panel will need to be replaced.

TROUBLE CODE DISPLAY

After the displays end the segment check, any trouble codes stored in computer memory will be displayed. If trouble codes are present, they will be displayed on ECC Head as follows:

1. Display of ECC trouble codes at 1.6 second intervals will begin with current codes being displayed prior to history codes. Each code will be displayed for a 1.6 second interval.

2. If car is equipped with a 5.7 liter engine, ECM current codes can be displayed under parameter -01.

3. Progressively higher numbered ECM codes, if present, will be displayed consecutively for 1.6 second intervals until the highest code present has been displayed.

Code display will be repeated until a button is depressed on the CCP.