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Home › Volvo › 1998 › S90 AW30-40 › Repair and Diagnosis › Engine Performance › System › Engine Controls - Tests W/Codes › Diagnostic Tests › DTC 153: Rear Ho2S Signal

DTC 153: Rear Ho2S Signal

  1. If fault is permanent or intermittent and signal is too high, perform diagnosis as per DTC 212. If fault is permanent and signal is too low, go to next step. If fault is permanent and signal is faulty, go to step 5). If fault is permanent and signal is missing, go to step 6). If fault is intermittent and signal is too low, go to step 9). If fault is intermittent and signal is faulty, go to step 10). If fault is intermittent and signal is missing, go to step 11).
  2. Connect Breakout Box (981-3190) to ECM. Turn ignition on. Connect voltmeter between breakout box pins No. 33 and 42. If voltmeter reads about .7 volt, go to next step. If voltmeter does not read about .7 volt, disconnect front HO2S connector. Turn ignition on. Recheck voltage between breakout box pins. If voltmeter reads about .7 volt, install new front HO2S. If voltmeter does not read about .7 volt, disconnect rear HO2S and repeat test. If voltmeter reads about .7 volt, install new rear HO2S. If voltmeter does not read about .7 volt, check wiring between front HO2S terminal No. 3 and ECM connector terminal A33, and wiring between rear HO2S terminal No. 3 and ECM connector terminal A19 for a short to ground.
  3. Turn ignition on. Connect voltmeter between breakout box pins No. 32 and 42. If voltage is about 1.2 volts, go to next step. If voltage is not about 1.2 volts, turn ignition off. Disconnect front HO2S connector. Repeat test. If voltage is now about 1.2 volts, replace front HO2S. If voltage is not about 1.2 volts, check wiring between front HO2S terminal No. 4 and ECM connector terminal A33 for a short to ground.
  4. Turn ignition off. Disconnect rear HO2S connector. Repeat test. Connect voltmeter between breakout box pins No. 34 and 42. If voltage is now about 1.2 volts, replace rear HO2S. If voltage is not about 1.2 volts, check wiring between rear HO2S terminal No. 4 and ECM connector terminal A34 for a short to ground.
  5. Turn ignition off. Wait 2 minutes. Disconnect rear HO2S connector. Connect ohmmeter between HO2S connector terminals No. 3 and 4. If at least 50 k/ohms are present, check wiring between rear HO2S terminal No. 4 and control module connector terminal A34 for a short circuit. If at least 50 k/ohms are not present, replace rear HO2S.
  6. Turn ignition off. Wait 2 minutes. Disconnect rear HO2S connector. Connect ohmmeter between HO2S connector terminals No. 4 and ground. If at least 50 k/ohms are present, go to next step. If at least 50 k/ohms are not present, check HO2S and ECM connectors for poor terminal contact. Repair as necessary. Repeat test. If at least 50 k/ohms are present, system is okay, If at least 50 k/ohms are not present, check wiring between rear HO2S connector terminal No. 4 and ECM connector terminal A34 for an open circuit.
  7. Ensure ignition is off. Connect ohmmeter between rear HO2S connector terminal No. 3 and ground. If ohmmeter reads about 140 ohms, go to next step. If ohmmeter does not read about 140 ohms, check HO2S and ECM connectors for poor terminal contact. Repair as necessary. Repeat test. If ohmmeter reads about 140 ohms, system is okay, If ohmmeter does not read about 140 ohms, check wiring between rear HO2S connector terminal No. 3 and ECM connector terminal A33 for an open circuit.
  8. Reconnect HO2S. Start and idle engine. Using scan tool, go into scrolling values list. If DTC is intermittent status, DTC was caused by poor terminal contact. If rear HO2S signal is not to specification, replace rear HO2S.
  9. Check wiring between front HO2S connector terminal No. 4 and ECM connector terminal A32 for an intermittent short to ground. Check wiring between front HO2S terminal No. 3 and ECM connector terminal A33, and between rear HO2S terminal No. 3 and ECM connector terminal A19 for an intermittent short circuit. Check wiring between rear HO2S terminal No. 4 and ECM connector terminal A34 for an intermittent short to ground. Repair as necessary.
  10. Check wiring between front HO2S connector terminal No. 4 and ECM connector terminal A34 for an intermittent short to wiring harness between front HO2S terminal No. 3 and ECM connector terminal A19. Repair as necessary.
  11. Check wiring between rear HO2S terminal No. 4 and ECM connector terminal A34 for an intermittent short circuit. Check wiring between rear HO2S terminal No. 3 and ECM connector terminal A19 for an intermittent open circuit. Check ECM and rear HO2S connectors for poor terminal contact. Repair as necessary.
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