LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Volkswagen >> 1996 >> Passat GLS, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - Gasoline >> Circuit Tests >> DTC P0140/16524 - Ho2S Circuit No Activity (Bank 1 Sensor 2)
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC P0140/16524 - Ho2S Circuit No Activity (Bank 1 Sensor 2)

NOTE: DTC is set when post-catalyst Heated Oxygen Sensor (HO2S) is dirty, aged or contaminated.
  1. Inspect pre-catalyst HO2S connector for looseness and/or corrosion. Repair sensor connector as necessary. Erase DTC memory and test drive vehicle. See CLEARING DTCS in this article. Recheck DTC memory and verify DTC does not reset. If DTC resets, go to next step. If sensor connector is okay, go to next step.
  2. Run engine at 3500 RPM for at least 3 minutes. Erase DTC memory and test drive vehicle. See CLEARING DTCS  in this article. Recheck DTC memory and verify DTC does not reset. If DTC does not reset, HO2S was dirty. If DTC resets, go to next step.
  3. Turn ignition off. Disconnect Electronic Control Module (ECM) connector. Connect Test Box (VAG 1598/18) to ECM wiring harness. Terminal assignments of test box are identical to ECM connector's.
  4. Disconnect post-catalyst HO2S connector. Using DVOM, check resistance between post-catalyst HO2S connector terminal No. 3 and test box socket No. 58, and post-catalyst HO2S connector terminal No. 4 and test box socket No. 13. Resistance should be less than 1.5 ohms. If resistance is as specified, go to next step. If resistance is not as specified, locate and repair open circuit between HO2S and ECM. Erase DTC memory and test drive vehicle. See CLEARING DTCS in this article. Recheck DTC memory and verify DTC does not reset. If DTC resets, go to next step.
  5. Turn ignition on. Jumper test box sockets No. 1 and 6. Using DVOM, check voltage between pre-catalyst HO2S connector terminal No. 1 and ground. Voltage must be at least 11.5 volts. If voltage is as specified, go to step 8). If voltage is not as specified, go to next step.
  6. Remove fuse No. 18. Using DVOM, check resistance between fuse No. 18 connector upper terminal and post-catalyst HO2S connector terminal No. 1. Resistance should be less than 1.5 ohms. If resistance is as specified, go to next step. If resistance is not as specified, locate and repair open circuit between pre-catalyst HO2S connector and ECM, and go to step 8). 7) Check resistance between HO2S terminals No. 1 and 2. Resistance should be 20 ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace HO2S and go to next step.
  7. If vehicle was repaired, clear DTCs and perform test drive. See CLEARING DTCS  in this article. Recheck DTC memory and verify DTC does not reset. If DTC resets, go to next step. If vehicle was not repaired, go to next step.
  8. Replace faulty ECM. Test drive vehicle. Recheck DTC memory and verify DTC does not reset. If DTC resets, repeat testing procedure.
scientia non olet · About LEMON Manuals