Diagnosis & Repair
- Access ECM harness connectors behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector. Measure voltage between terminals HT1, HT2, and ground. See Figure. Voltage for each circuit should be 9-14 volts.
- If voltage is within specification, replace ECM and retest. If voltage is NOT within specification, turn ignition off. Disconnect oxygen sensor harness connector. Using ohmmeter, measure resistance between sensor connector terminals No. 1 and 2. See Fig 1.
- Resistance should be 11-16 ohms at 68°F (20°C). If resistance for sensor is within specification, inspect circuits between ECM and sensor. See wiring diagram in the WIRING DIAGRAMS
article. Repair as needed. If resistance is NOT within specification, replace sensor and retest.
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