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Home › Saturn › 1996 › SW2 Automatic › Repair and Diagnosis › Engine Performance › System › Engine Controls - Tests W/Codes › Diagnostic Trouble Codes › DTC P0141 - Ho2S Heater Circuit Sensor 2 › Diagnostic Procedures

Diagnostic Procedures

  1. Install scan tool. Turn ignition on, with engine off. Using scan tool, observe rear HO2S voltage reading immediately after turning ignition on. If voltage is 350-550 mV, go to next step. If voltage is not 350-550 mV, allow exhaust system to cool down.
  2. Voltage should gradually change toward zero volts or toward one volt, within 2 minutes after turning ignition on. If voltage change is as specified, problem is intermittent. If voltage change is not as specified, go to next step.
  3. Turn ignition off. Disconnect HO2S No. 2 harness connector. Turn ignition on. Using a test light connected to ground, probe HO2S harness connector terminal "D". If test light illuminates, go to next step. If test light does not illuminate, repair open in ignition circuit to HO2S No. 2.
  4. Connect test light between HO2S harness connector terminals "C" and "D". If test light illuminates, check 4-pin harness connector terminals. If terminals are okay, replace HO2S NO. 2. If test light does not illuminate, repair open in ground circuit to HO2S No. 2.
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