Checking the technical condition of the control system of gasoline engines (Hyundai Tucson LM)

1. Check the engine control unit (ECM) "mass" circuit: Measure the resistance between the electronic engine control unit (ECM) and the chassis "mass" using the back of the wiring harness connector (ECM) on the engine control unit (ECM) side as a reference point. If a problem is detected, correct it.

Note: Resistance: less than 1 ohm.

2. Checking the Engine Control Module (ECM) Connector: Disconnect the Engine Control Module (ECM) connector and visually inspect the ECM-side and harness-side ground terminals for bent contacts or poor contact pressure. If a fault is found, repair it.

3. If the fault is not detected in steps 1 and 2, the engine control module (ECM) may be faulty. In this case, before replacing the module with a new one, check for fault codes. After replacing the module, retest the vehicle. If fault codes appear, they must be checked before replacing the module.

4. Recheck the original electronic control unit (ECM). Install the original unit (possibly faulty) in a known good car and check. If the problem reoccurs, replace the original unit with a new one. If everything is OK, then the fault is intermittent.

(The original text is located on the portal: HyundaiBook)