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Pcm Code E45, Oxygen (O2) Sensor Rich Exhaust Signal: Action

PCM turns on SERVICE ENGINE SOON light. PCM turns off canister purge solenoid and air management solenoids. PCM switches to "open loop" operation.

NOTE: Test numbers refer to numbers on diagnostic chart.
  1. With O2 sensor disconnected, parameter P.1.4 should remain at reference voltage (.38-.63 volt).
  2. Checks for PCM ability to recognize lean input on O2 sensor signal circuit No. 412.
  3. PCM compares O2 sensor signal voltage received on circuit No. 412 to ground voltage on circuit No. 413. If PCM does not have a good ground to engine on circuit No. 413, O2 sensor reading can falsely appear high or low. With engine running, use a voltmeter to measure voltage from O2 sensor at exhaust manifold to PCM terminal E15. If voltage is -.05 to +.05 volt, ground is okay. If voltage is less than -.05 volt or greater than +.05 volt, repair poor ground on circuit No. 413 between PCM terminal E15 and ground at front of right cylinder head.
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