Test 3: Electronic-Controlled A/T Communication Circuit
WARNING: This page is about a different car, the 1997 Lexus SC 300. However, it is still accessible from the selected car via links, so may be relevant.
- Warm engine to operating temperature. Drive vehicle to ensure overdrive operates. If overdrive does not operate, repair transmission. If overdrive operates, remove cruise control ECU. Disconnect electrical connector from cruise control ECU. Turn ignition on. At cruise control ECU connector, measure voltage between ground and terminal No. 9. See Figure.
- Voltage should be 10-14 volts. If voltage is as specified, go to next step. If voltage is not as specified, check for faulty circuit between cruise control ECU and engine/transmission ECM. Repair circuit if necessary. If circuit is okay, replace engine/transmission ECM.
- Turn ignition off. Reconnect electrical connector to cruise control ECU. Warm engine to operating temperature. Connect voltmeter between ground and cruise control ECU connector terminal No. 22. See Figure.
- While driving vehicle, have an assistant watch voltmeter. With OD on, battery voltage should be present. With OD off, less than one volt should be present.
- If voltage is as specified, perform next procedure listed in DIAGNOSIS BY SYMPTOM table under TROUBLE SHOOTING. If voltage is not as specified, check for faulty circuit between cruise control ECU and shift solenoid No. 2. Repair circuit if necessary. If circuit is okay, replace cruise control ECU.