Related Tests, Information and Procedures

NOTE: Make sure the vehicle being tested has a fully charged battery. If it does not, false diagnostic codes or error messages may occur.

WARNING: Some components of the powertrain system are intended to be serviced in assembly only. Attempting to remove or repair certain system sub-components may result in personal injury and/or improper system operation. Only those components with approved repair and installation procedures should be serviced.

These procedures include all the specifications, instructions, and graphics needed to diagnose powertrain control module (PCM) problems; they are No Start, Diagnostic Trouble Code, and No Trouble Code problems for the PCM. These diagnostic charts are based on the trouble condition or symptom being present at the time of diagnosis.

Diagnostic procedures change every year. New diagnostic systems may be added; carryover systems may be enhanced. IT IS RECOMMENDED THAT YOU REVIEW DESCRIPTION OF ON-BOARD DIAGNOSTICS TO BECOME FAMILIAR WITH ALL NEW AND CHANGED DIAGNOSTIC PROCEDURES.

These charts are designed to begin all diagnosis at the Trouble Code (TC) Test/DTC TEST. This test covers all the necessary requirements to begin a logical diagnostic path for each problem. If there is a trouble code (DTC) detected, it will direct you to the trouble code test. If there are no trouble codes present, it will direct you by symptom to a no-trouble code test.

Diagnosis of the powertrain control module (PCM) is done in six basic steps:
- Verify Of Complaint
- Verify Any Related Symptoms
- Analyze Symptoms
- Isolate the Problem
- Repair Isolated Problem
- Verify Repair

Electronic Pinion Factor
The VSS supplies distance pulses to the powertrain control module (PCM), which are used to calculate speed and mileage. A pinion factor is stored in the transmission control module (TCM) in order to provide the appropriate distance pulses for the vehicle. The pinion factor is programmed into the TCM at the assembly plant.

Electronic Pinion Factor Warning
The pinion factor must be set for all new transmission control modules. If the pinion factor is not set or if it is set incorrectly, any speed-related accessories will not operate or will operate inaccurately. This includes the speedometer, speed control, rolling door locks, and other devices that are operated by the powertrain and body control modules. For instructions on setting the pinion factor, see Transmission Control Systems.