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DTC P0141: 1/2 O2 Sensor Heater Failure

NOTE: For connector terminal identification, see CONNECTOR IDENTIFICATION  . For circuit identification and wiring diagram, see WRANGLER wiring diagram in WIRING DIAGRAMS article.
NOTE: DTC P0141: 1/2 O2 SENSOR HEATER FAILURE is monitored with engine at idle immediately after a cold start, with engine coolant temperature less than 147°F (63.9°C) and ambient/battery temperature within 27°F (2.8°C), plus or minus, of engine coolant temperature. DTC may be stored in Powertrain Control Module (PCM) when PCM senses that 1/2 Heated Oxygen Sensor (HO2S) voltage is more than 3 volts for 30-90 seconds. Possible causes are: engine mechanical problem, exhaust leak, defective 1/2 HO2S, defective connectors or defective wiring.
NOTE: 1/2 HO2S is located in downstream position.
  1. Using scan tool, read DTCs. If DTC SPECIFIC GOOD TRIP COUNTER is displayed and displayed count is "0", go to next step. If DTC SPECIFIC GOOD TRIP COUNTER is not displayed or displayed count is not "0", go to step 3).
  2. Turn ignition on, with engine off. Using scan tool in SENSOR mode, wait for 1/2 HO2S voltage to reach 4.5 volts (about 3 minutes). Using scan tool in ACTUATOR mode, perform and monitor 1/2 HO2S HEATER TEST voltage for 3 minutes. If voltage is more than one volt, go to step 4). If voltage is one volt or less, go to next step.
  3. At this time, DTC P0141: 1/2 O2 SENSOR HEATER FAILURE does not exist or is an intermittent problem. Using scan tool, read and record FREEZE FRAME data. Road test vehicle under conditions in FREEZE FRAME data, paying particular attention to fault setting conditions such as speed, temperature, load and MAP vacuum. Using scan tool, read DTCs. If DTC P0141: 1/2 O2 SENSOR HEATER FAILURE returns, go to next step. If DTC P0141: 1/2 O2 SENSOR HEATER FAILURE does not return, see INACTIVE DTC CONDITION  . Test is complete.
  4. Turn ignition off. Disconnect 1/2 HO2S connector. Visually inspect connector for corroded, damaged, pushed-out or miswired terminals. Repair connector as necessary. Perform TEST VER-5A3. If connector is okay, go to next step.
  5. Turn ignition on, with engine off. Ensure 1/2 HO2S connector is still disconnected. Using scan tool in ACTUATOR mode, perform 1/2 HO2S HEATER TEST. Using a voltmeter, check voltage on 1/2 HO2S connector, ASD relay output circuit (Orange/Dark Green wire). If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open ASD relay output circuit. Perform TEST VER-5A3.
  6. Ensure 1/2 HO2S connector is still disconnected. Using an ohmmeter, check resistance across 1/2 HO2S connector (component side), heater element circuits (White wires). If resistance is 4-7 ohms, go to next step. If resistance is not 4-7 ohms, replace 1/2 HO2S. Perform TEST VER-5A3.
  7. Ensure 1/2 HO2S connector is still disconnected. Using ohmmeter, check resistance between ground and 1/2 HO2S connector, heater ground circuit (Black wire). If resistance is less than 5 ohms, replace 1/2 HO2S. Perform TEST VER-5A3. If resistance is 5 ohms or more, repair open heater ground circuit. Perform TEST VER-5A3.
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