Diagnosis & Repair
WARNING: This page is about a different car, the 2000 Toyota Sienna. However, it is still accessible from the selected car via links, so may be relevant.
- Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 2 (Yellow wire) and No. 18 (Brown wire) at ECM harness connector E11. See Figure. If voltage is not 4.5-5.5 volts, replace ECM. If voltage is 4.5-5.5 volts, go to next step.
- Using DVOM, backprobe ECM harness connector and measure voltage between terminal No. 17 (Blue/Red wire) at ECM harness connector E8 and terminal No. 18 (Brown wire) at ECM harness connector E11. See Figure. Disconnect vacuum hose from vapor pressure sensor. Connect a vacuum pump to vapor pressure sensor. Voltage should be 2.9-3.7 volts without vacuum applied and .5 volt or less with 1.18 in. Hg applied. If voltage is as specified, replace ECM. If voltage is not as specified, go to next step.
- Check for open or short in wiring between vapor pressure sensor and ECM. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace vapor pressure sensor.