About Diagnostic Charts/Electronic Pinion Factor

Always begin by reading the diagnostic trouble codes using a scan tool.
- This procedure begins in Trouble Code (TC) Tests, Checking for Diagnostic Trouble Codes DTC Test - CODE TO TC TEST CHART (Checking for Trouble Codes). This will direct you to the specific test(s) that must be performed.

The procedures contained 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 diagnostics are based on the trouble condition or symptom being present at the time of diagnosis.

When repairs are required, refer to the appropriate removal and repair procedure.

Diagnostic procedures change every year. New diagnostic systems may be added; carryover systems may be enhanced. READ THE GENERAL INFORMATION SECTIONS BEFORE TRYING TO DIAGNOSE A VEHICLE TROUBLE CODE. It is recommended that you review as much as possible to become familiar with new or revised diagnostic procedures.

Electronic Pinion Factor
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. (Use scan tool and follow manufacturer's instructions).