1993 Acura Integra GS-RFACTORY OEM SERVICE PROCEDURE

Code 41: Ho2S Heater

  1. Turn ignition off. Remove BACK-UP fuse (7.5-amp) from underhood fuse/relay box for 10 seconds to reset ECM. Check ECM for fault codes. If Code 41 is not present, problem is intermittent. Check for poor connections at ECM, HO2S and wiring harness connectors.
  2. Test drive vehicle and retest. If Code 41 is present, turn ignition off. Disconnect 4-pin HO2S connector. Measure resistance between HO2S terminals "C" and "D". See Fig 1 . If resistance is not 10-40 ohms, replace sensor. If resistance is 10-40 ohms, go to step 3.
    Fig 1: Identifying HO2S Connector Terminals
    G92A26229Courtesy of AMERICAN HONDA MOTOR CO., INC.
  3. Check for continuity between body ground and HO2S terminals "C" and "D". If continuity is present, replace sensor. If continuity is not present, check for continuity between terminal "D" and terminals "A" and "B". If continuity is present, replace sensor.
  4. If continuity is not present, turn ignition on. Measure voltage between Yellow/Black (+) and Orange/Black (-) wire terminals at HO2S wiring harness connector. See Fig 1 . If battery voltage is not present, go to step 7. If battery voltage is present, disconnect connector "A" from ECM. Measure voltage between Yellow/Black (+) and Orange/Black (-) wires at HO2S wiring harness connector.
  5. If battery voltage is present, repair short circuit in Orange/Black wire between ECM connector terminal A6 and HO2S. If battery voltage is not present, reconnect HO2S. Connect connector "A" of ECM Test Harness (07LAJ-PT3010A ) to vehicle wiring harness, leaving ECM disconnected.
  6. Connect ammeter between test terminals A6 (+) and A23 (-). Monitor ammeter for 5 minutes. If current is less than 0.1 amp, replace HO2S. If current is not less than 0.1 amp, replace ECM and retest.
  7. If battery voltage did not exist in step 4, measure voltage between Yellow/Black wire terminal (+) at HO2S wiring harness connector and body ground. If battery voltage does not exist, repair open in Yellow/Black wire between HO2S and main relay. If battery voltage exists, turn ignition off. Reconnect HO2S wiring harness connector.
  8. Connect connector "A" of ECM Test Harness (07LAJ-PT3010A ) to ECM wiring harness, leaving ECM disconnected. Turn ignition on. Measure voltage between test terminals A6 (+) and A23 (-). If battery voltage does not exist, repair open in Orange/Black wire between ECM connector terminal A6 and HO2S. If battery voltage exists, replace ECM and retest.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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