DTC P0141: 1/2 O2 Sensor Heater Failure: Testing
- Turn ignition on, engine off. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0141 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0141 or displayed count is not "0", go to step 3.
- Turn ignition off. Wait a minimum of 8 minutes to allow 1/2 HO2S to cool down (voltage should stabilize to 0.4-0.6 volt). Turn ignition on, engine off. Using scan tool, actuate HO2S HEATER TEST and monitor 1/2 HO2S voltage for 2 minutes. If voltage stays at 0.4-0.6 volt, go to next step. If voltage does not stay at 0.4-0.6 volt, go to step 7.
- Turn ignition off. Allow 1/2 HO2S to cool down to room temperature. Disconnect 1/2 HO2S connector. Measure resistance between 1/2 HO2S connector heater element terminals No. 1 and No. 2. See Figure. Resistance should be within specification. See O2 SENSOR HEATER RESISTANCE SPECIFICATIONS table in DTC P0032. If resistance is not within specification, replace 1/2 HO2S. If resistance is within specification, 1/2 HO2S heater element is okay. Go to next step.
- Ensure ignition is off. Disconnect PCM connectors. PCM is located in engine compartment on passenger-side inner fender panel. On California models, measure resistance of heater ground circuit between 1/2 HO2S harness connector and ground point. Ground point is located on right front side of engine block. On non-California models, measure resistance of PWM heater control circuit between 1/2 HO2S harness connector and PCM harness connector C3 terminal No. 16. See 1/2 HO2S TERMINAL IDENTIFICATION table. See Figure. On all models, if resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in appropriate wire between 1/2 HO2S, ground point or PCM.
- Ensure ignition is off and 1/2 HO2S is still disconnected. Reconnect PCM connectors. Turn ignition on, engine off. Using scan tool, actuate HO2S HEATER TEST. Measure voltage between ground and fused ignition circuit at 1/2 HO2S harness connector. See 1/2 HO2S TERMINAL IDENTIFICATION table. See Figure. If voltage is more than 11 volts, go to next step. If voltage is 11 volts or less, repair open in appropriate wire between 1/2 HO2S, oxygen sensor relay or joint connector No. 1 in Power Distribution Center (PDC). PDC is located in engine compartment, next to battery. See WIRING DIAGRAMS article.
- At this time, PCM is assumed to be defective. Replace PCM.
- At this time, conditions for DTC P0141 to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor 1/2 HO2S voltage while wiggling connectors and wiring harness from 1/2 HO2S to Powertrain Control Module (PCM). PCM is located in engine compartment on passenger-side inner fender panel. If voltage changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused voltage to change. If voltage does not change, review FREEZE FRAME DATA using scan tool. Attempt to duplicate condition that caused DTC P0141 to set by paying special attention to the conditions during which 1/2 HO2S is monitored. Check for any related Technical Service Bulletins (TSBs) that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.