On-Board Diagnostics

General Notes

A problem with the EC-AT may be caused by the engine, the EC-AT powertrain, the hydraulic control system, or the electronic control system; therefore, when troubleshooting begin with those points which can be inspected quickly and easily. The recommended troubleshooting sequence is described below.

Caution: Be aware that this section deals with the powertrain control module. It is Interconnected for the FS engine.

Step 1: On-Boad Diagnostic System Inspection






Check for diagnostic trouble code(s) memorized in the powertrain control module (PCM) with the super star II tester. Refer to Computers and Control Systems.

Note: Diagnostic trouble code(s) can also be checked for by the flashing sequence of the hold indicator light.

Step 2: Electrical Signal Inspection






Check the signals to/from the powertrain control module (PCM) with the voltmeter and the breakout box.

Step 3: Mechanical System Test






Check the engine stall speed, line pressure.

Step 4: Road Test






Check the shift point, shift schedule, and shift shock.