Diagnostic Procedure
WARNING: This page is about a different car, the 2002 Toyota Avalon. However, it is still accessible from the selected car via links, so may be relevant.
- Check vehicle speed sensor. See INSTRUMENT PANELS - AVALON article. If vehicle speed sensor is okay, go to next step. If vehicle speed sensor is defective, replace vehicle speed sensor. After repairs, perform confirmation test. See CONFIRMATION TEST .
- Turn ignition off. Disconnect cruise control ECU 16-pin electrical harness connector. Using DVOM, check cruise control ECU ground circuit. See CRUISE CONTROL in SYSTEM WIRING DIAGRAMS article. If ground circuit is faulty, repair and retest system. If ground circuit is okay, substitute original cruise control ECU with a known-good unit and recheck system operation. If system operates properly, original cruise control ECU was defective. If system still does not operate properly, perform cruise control ECU pin voltage check. See PIN VOLTAGE TESTS . Check wiring harness and electrical connectors for an intermittent problem. Repair wiring harnesses or connectors as necessary. See CRUISE CONTROL in SYSTEM WIRING DIAGRAMS article. If voltage values, harnesses and connectors are okay, replace cruise control ECU. See CRUISE CONTROL ELECTRONIC CONTROL UNIT under REMOVAL & INSTALLATION. After repairs, perform confirmation test. See CONFIRMATION TEST .