Diagnosis & Repair
WARNING: This page is about a different car, the 2000 Toyota Tundra. 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. On models with California emissions, measure voltage between terminals No. 2 (Green/Black wire) and No. 18 (Green/White wire) at ECM harness connector E5. See Figure. On models without California emissions, measure voltage between terminals No. 1 (Green/Black wire) and No. 22 (Green/White wire) at ECM harness connector E5. See Figure. On all models, voltage should be 4.5-5.5 volts. If voltage is not as specified, replace ECM. If voltage is as specified, go to next step.
- Using DVOM, backprobe ECM harness connector. On models with California emissions, measure voltage between terminal No. 17 (Red/Green wire) at ECM harness connector E3 and terminal No. 18 (Green/White wire) at ECM harness connector E5. See Figure. On models without California emissions, measure voltage between terminal No. 13 (Red/Green wire) at ECM harness connector E4 and terminal No. 22 (Green/White wire) at ECM harness connector E5. See Figure. On all models, disconnect vacuum hose from vapor pressure sensor. Connect a vacuum pump to vapor pressure sensor. Voltage should be 3.0-3.6 volts without vacuum applied and .5 volt or less with 1.8 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.