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.
- Insert registered master key into ignition lock cylinder. A master key is a Black-colored ignition key that opens all locks. Remove glove box for access to ECM. ECM is located behind glove box and contains 5 electrical connectors. See Figure.
- Backprobing with an oscilloscope or Toyota hand-held tester, check for noise in the scope pattern at terminal No. 28 (Pink/Green wire) of ECM electrical connector E7. See Figure. This is the wire that goes from CODE terminal on ECM to the transponder key amplifier. Transponder key amplifier is located near upper steering column bracket. See Figure. Noise will be displayed as indicated in the scope pattern. See Fig 1. If no noise is detected, go to next step. If noise is detected, find where noise interference is coming from and repair as necessary. After repairs have been made, perform confirmation test. See CONFIRMATION TEST under SYSTEM TESTS.
- Replace transponder key amplifier with a known-good unit. See TRANSPONDER KEY AMPLIFIER under REMOVAL & INSTALLATION. Check system operation. If engine still will not start after replacing original transponder key amplifier, go to next step. If engine starts after replacing original transponder key amplifier, no further testing is required at this time, as the original transponder key amplifier was defective. After repairs have been made, perform confirmation test. See CONFIRMATION TEST under SYSTEM TESTS.
- Check Engine Control Module (ECM) ground circuits. See ANTI-THEFT in SYSTEM WIRING DIAGRAMS article. If ground circuits are faulty, repair and retest system. If ground circuits are okay, substitute original ECM with a known-good unit and recheck system operation. If system operates properly, original ECM was defective. If system still does not operate properly, perform ECM pin voltage check. See PIN VOLTAGE TESTS . Check wiring harness and electrical connectors for an intermittent problem. Repair wiring harnesses or connectors as necessary. If voltage values, harnesses and connectors are okay, replace ECM. After repairs have been made, perform confirmation test. See CONFIRMATION TEST .