Diagnostic Procedure
WARNING: This page is about a different car, the 2002 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.
- Warm up the engine. Turn the ignition switch to the OFF position. Connect the scan tool to the DLC3. Turn the ignition switch to the ON position and turn the scan tool ON. Select the item "SPD (NC)" in the DATA LIST and read its value displayed on the scan tool. Does the counter gear read at least 50 RPM? If so, replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article in ENGINE PERFORMANCE. If not, go to next step.
- Disconnect the speed sensor wiring connector at the speed sensor and measure the resistance between the terminals. See Fig 1. Resistance should be 500-620 ohms at 68°F (20°C) for Toyota made sensors, and 560-680 ohms at 68°F (20°C) for ASIAN made sensors. If readings are within specification, go to next step. If not, replace speed sensor.
- Connect the speed sensor connector. Disconnect the ECM connector. Measure the resistance between terminal NC+ and NC-. Resistance should be 500-620 ohms at 68°F (20°C) for Toyota made sensors, and 560-680 ohms at 68°F (20°C) for ASIAN made sensors. If readings are within specification, replace ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article in ENGINE PERFORMANCE. If not, repair or replace wiring harness and connector.