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DTC P0043: Rear Ho2S Heater Circuit Low: Testing

NOTE: Ensure freeze frame data has been recorded. Check for service bulletins and on-line information.
  1. Turn ignition off. Disconnect O2 sensor. Check connectors for damaged terminals and corrosion. If no problem is found, go to next step. If problem is found, repair as necessary. After repair, go to step  7 .
  2. Check resistance between sensor connector terminals "A" and "B". If resistance is about 16 ohms, go to next step. If resistance is not about 16 ohms, replace O2 sensor and go to step  7 .
  3. Turn ignition on. Check voltage between O2 harness connector terminal "A" (Black/White wire) and ground. If battery voltage is present, go to next step. If battery voltage is not present, repair open on circuit between sensor and main relay and go to step  7 .
  4. Turn ignition off. Disconnect PCM connector. PCM is mounted to passenger floor, behind glove box. Check harness connector and PCM terminal No. 96 for damaged terminals and corrosion. If no problem is found, go to next step. If problem is found, If problem is found, repair as necessary. After repair, go to step  7 .
  5. Check continuity between O2 sensor harness connector terminal "B" (Light Green wire) and ground. If continuity is not present, go to next step. If continuity is present, repair short to ground on circuit between harness connector and PCM. After repair, go to step  7 .
  6. Connect breakout box to harness connector. Leave PCM disconnected. Check continuity between O2 sensor harness connector terminal "B" (Light Green wire) and breakout box terminal No. 96 (Green/Orange wire). If continuity is present, go to next step. If continuity is not present, repair open on circuit between harness connector and PCM. After repair, go to next step.
  7. Reconnect all components. Using scan tool, clear DTC. Start engine and allow to reach operating temperature. Using scan tool, check for DTC P0043. If DTC P0043 is not pending, go to next step. If DTC P0043 is pending, replace PCM and go to next step.
  8. Perform after repair procedure. See AFTER REPAIR PROCEDURE  . If no DTC is present, testing is complete. If any DTC is present, go to appropriate test for diagnosis and repair.
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