Test TC-122A - Left Upstream O2 Sensor Slow Response
NOTE:
For connector terminal ID, see CONNECTOR IDENTIFICATION DIRECTORY table. For wiring diagram, see WIRING DIAGRAMS - 3.3L
article.
- LEFT UPSTREAM O2 SENSOR SLOW RESPONSE DTC sets if left upstream O2 sensor signal voltage is switching from less than .39 volt to more than .6 volt and back fewer times than required. Possible causes are: exhaust leak, fuel contamination, dirty or wet O2 sensor connector causing voltage tracking or engine mechanical failure. Go to next step.
- Start engine. Check for exhaust system leaks between engine and catalytic converter. If no exhaust system leaks are found, go to next step. If exhaust system leaks are found, repair exhaust system as necessary. Perform TEST VER-5A .
- Check exhaust for excessive smoke from oil or coolant consumption. If oil or coolant consumption is not present, go to next step. If oil or coolant consumption is present, repair engine mechanical failure as necessary. Replace left upstream O2 sensor. Perform TEST VER-5A .
- Turn ignition off. Disconnect left upstream O2 sensor connector. Inspect connectors. If any terminal is corroded, damaged, pushed out or miswired, repair as necessary. Perform TEST VER-5A . If connectors are okay, go to next step.
- Using an ohmmeter, measure resistance between ground and sensor ground circuit at left upstream O2 sensor harness connector terminal No. 3 (Black/Light Blue wire). If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in sensor ground circuit. Perform TEST VER-5A .
- Disconnect Powertrain Control Module (PCM) connector. Inspect connectors. If any terminal is corroded, damaged, pushed out or miswired, repair as necessary. Perform TEST VER-5A . If connectors are okay, replace left upstream O2 sensor. Perform TEST VER-5A .