Diagnostic Procedure
NOTE:
If not using a Lexus/Toyota scan tool, start diagnosis at step 2.
- Connect a Lexus/Toyota scan tool to the DLC3. Turn the ignition switch to the ON position and turn the scan tool ON. Read the PATTERN SEL SW signal on the scan tool. Place the pattern select switch in the PWR position. Scan tool should read ON. Place the pattern select switch in the NORM mode. The scan tool should read OFF. If the scan tool displays the specified value, see SYMPTOM DIAGNOSIS . If the scan tool does not display specified value, go to step 3.
- Turn the ignition switch to the ON position. Measure the voltage between terminal PWR of appropriate ECM harness connector and ground when the pattern select switch is set to the PWR position (less than 1.5 volts) and the NORM position (10-14 volts). See Figure and Figure . Are the switch readings within specification? If so, see SYMPTOM DIAGNOSIS . If not, go to next step.
- Disconnect the pattern select switch connector. Check continuity between terminals No. 3 and 5 of pattern select switch connector when the select switch is set to PWR (continuity) and NORM (no continuity) positions. See Fig 1. Is the switch continuity as specified? If so, go to next step. If not, replace the pattern select switch.
- Check the wiring harness and connector for an intermittent condition. If wiring harness and connector are okay, replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article in ENGINE PERFORMANCE.