DTC Confirmation Test (Overall Function Check)

NOTE: Use the following test to check overall function of A/T control circuits. During this test, DTC may not be confirmed.

NOTE: Before performing confirmation test, ensure battery voltage is greater than 11 volts when engine is idling.

A/T control circuits are used to control shifting during hard acceleration or deceleration. Malfunction is detected when ECM receives incorrect voltage from Transmission Control Module (TCM). Possible cause is:

Open or short in circuit between TCM and ECM.

Connect scan tool to Data Link Connector (DLC). See Figure. Turn ignition on. Using scan tool, select DATA MONITOR. Wait at least 10 seconds. If first trip DTC is set, perform DIAGNOSTIC PROCEDURE . If first trip DTC is not set, problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.