J: Programmable Speedometer/Odometer Module (PSOM) Introduction

J: Pinpoint Tests

F-Series

Note

Enter this pinpoint test only when directed here from symptom flowcharts.

Remember

To prevent the replacement of good components, the following areas may be of concern:

• vehicle speed control system
• rear anti-lock brake system
• ring gear inside differential
• instrumentation system

This pinpoint test is intended to diagnose the following:

• programmable speedometer/odometer module (PSOM) output to the powertrain control module (PCM) (12A650)
• harness circuits: PSOM(+) PSOM(-)
• powertrain control module

Description

The PSOM receives input from the rear anti-lock brake system (RABS) sensor, which is mounted on the rear axle differential. The output produced by the PSOM is used by the PCM and speed control servo/amplifier assembly as a VSS.

J: Pinpoint Tests