DTC P0116/16500: Engine Coolant Temperature Sensor Implausible Signal, DTC P0117/16501: Engine Coolant Temperature Sensor Signal Too Small &/Or DTC P0118/16502: Engine Coolant Temperature Sensor Signal Too Large
- Turn ignition off. Disconnect Engine Coolant Temperature (ECT) sensor 4-pin connector. ECT is located at rear of cylinder head. Inspect ECT sensor connector for looseness and/or corrosion. If no problem is found, go to next step. If problem is found, repair as necessary. After repair, go to step 5.
- Using DVOM, measure resistance between ECT sensor pins "C" and "D". See Fig 1. Resistance should be as specified. See Fig 2. If resistance readings are not as specified, go to next step. If resistance readings are as specified, go to step 5.
- Disconnect Engine Control Module (ECM) harness connectors. ECM is located in left rear corner of engine compartment, in electronics box. Connect VAG 1598/31 test box to ECM wiring harness (leave ECM disconnected). Check for open, short to voltage, short to ground or short to each other in circuits between ECT sensor connector terminals and specified test box sockets. See CHECKING ENGINE COOLANT TEMPERATURE SENSOR CIRCUITS table. See Fig 3. If no problem is found, go to next step. If problem is found, repair as necessary. After repair, go to step 5.CHECKING ENGINE COOLANT TEMPERATURE SENSOR CIRCUITS
Engine Coolant Temperature Sensor Terminal VAG Test Box Socket 3 108 4 (Signal) 93 - Replace ECT. See REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
- Using scan tool, clear DTCs and generate a ECM readiness code. See FUNCTION 05 - CLEARING DIAGNOSTIC TROUBLE CODES and READINESS CODE under SELF-DIAGNOSTIC SYSTEM. Test drive vehicle. Using scan tool, retrieve DTCs. If DTC does not reset, testing is complete.