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DTC P0117/16501 - ECT Sensor Circuit Low Input

NOTE: DTC is set when Electronic Control Module (ECM) detects a short circuit in Engine Coolant Temperature (ECT) sensor or in ECT sensor circuit.
  1. Inspect ECT sensor 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. Turn ignition off. Disconnect ECT sensor connector. Disconnect ECM connector. Connect Test Box (VAG 1598/18) to ECM wiring harness. Terminal assignments of test box are identical to ECM connector's.
  3. Using a DVOM, check resistance between test box sockets No. 14 and 33. See ECT SENSOR RESISTANCE table below. If resistance is as specified, go to step 6). If resistance is not as specified, go to next step.
    ECT SENSOR RESISTANCE

    Temperature Ohms
    86°F (30°C) 1500-2000
    176°F (80°C) 275-375
  4. Using DVOM, check resistance between ECT sensor connector terminal No. 1 and test box socket No. 14. Resistance should be less than 1.5 ohms. infinite (no continuity). If resistance is as specified, go to step 6). If resistance is not as specified, repair open circuit between ECT sensor and ECM. Test drive vehicle. Recheck DTC memory and verify DTC does not reset. If DTC resets, go to next step.
  5. Check resistance between ECT sensor connector terminal No. 1 and test box socket 33. Resistance should be infinite (no continuity). If resistance is as specified, go to next step. If resistance is not as specified, repair short circuit to ground between ECT sensor connector 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.
  6. Carefully release cooling system pressure. Remove ECT sensor and plug hole in engine block. Check resistance between ECT sensor terminals No. 1 and 3 on 2.0L, or terminals No. 1 and 2 on 2.8L. Resistance must increase steadily as sensor cools or decrease as sensor is heated (such as with a hair dryer). If resistance is not as specified, replace ECT sensor. 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 resistance is as specified, go to next step.
  7. Replace faulty ECM. Test drive vehicle. Recheck DTC memory and verify DTC does not reset. If DTC resets, repeat testing procedure.
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