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.

When troubleshooting, therefore, 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 EC-AT control unit and the engine control unit for the K8 DOHC, and B6 SOHC engines. These two control units are separates for the B6 SOHC (California) and K8 DOHC engine, but are interconnected for the B6 SOHC except California engine.




Step 1: Self-diagnosis Function
Use the SST (EC-AT Tester, Self-Diagnosis Checker or DT-S1000) to check for service code(s) memorized in the EC-AT control unit [B6 SOHC (California) and K8 DOHC] or engine control unit (includes EC-AT CU) [B6 SOHC except California].




Step 2: Electric Signal Inspection

NOTE: Signals can also be checked by measuring the EC-AT control unit terminal voltages with a SST (Engine Signal Monitor) or voltmeter.

Use the SST (EC-AT Tester) to check the signals to/from the EC-AT control unit. Electrical Signal Inspection




Step 3: Mechanical System Test
Measure the engine stall speed, time lag, line pressure, and throttle pressure. Mechanical System Tests




Step 4: Road Test

NOTE: For the most correct testing, the vehicle speed, engine speed, throttle opening (throttle sensor voltage), and gear position should be checked with the EC-AT Tester.

Check the shift point, shift schedule, and shift shock. Mechanical System Tests

If the 4 steps on page K-12 are followed, the cause of the problem should be easily located. Another guide to fast location of the causes of problems is the Quick Diagnostic Chart. Quick Diagnosis Chart

In the chart, numbers are used to indicate the components that may be the cause of 24 possible problems. It is necessary to check only those components indicated by numbers during each step of the troubleshooting process to quickly locate the cause of the problem.