Hyundai Sonata LF: Emission Control System

Advanced Smart Cruise Control (ASCC) ECU Repair procedures

Removal 1. Turn the ignition switch OFF and disconnect the battery negative (-) terminal. 2. Disconnect the ASCC ECU connector (A). 3. Remove the ASCC ECU (C) after remove the installation nut (B)...

General Information

Description and Operation Description Emissions Control System consists of three major systems. • Crankcase Emission Control System prevents blow-by gas from releasing into the atmosphere...

Other information:

Hyundai Sonata LF 2014-2019 Service Manual: Repair procedures

On-vehicle Inspection Inspect ignition coil assembly and Perform spark test 1. Check for DTCs.     • If a DTC is present, perform troubleshooting in accordance with the procedure for that DTC. (Refer to DTC guide) 2...

Hyundai Sonata LF 2014-2019 Service Manual: Troubleshooting

Trouble Symptom Charts Trouble Symptom 1 Trouble Symptom 2 Trouble symptomProbable causeRemedyThe set vehicle speed varies greatly upward or downward"Surging" (repeated alternating acceleration and deceleration) occurs after settingMalfunction of the vehicle speed sensor circuitRepair the vehicle speed sensor system, or replace the partMalfunction of ECMCheck input and output signals at ECM Trouble Symptom 3 Trouble symptomProbable causeRemedyThe CC system is not canceled when the brake pedal is depressedDamaged or disconnected wiring of the brake pedal switchRepair the harness or replace the brake pedal switchMalfunction of the ECM signalsCheck input and output signals at ECM Trouble Symptom 4 Trouble symptomProbable causeRemedyThe CC system is not canceled when the shift lever is moved to the "N" position (It is canceled, however, when the brake pedal is depressed)Damaged or disconnected wiring of inhibitor switch input circuitRepair the harness or repair or replace the inhibitor switchImproper adjustment of inhibitor switchMalfunction of the ECM signalsCheck input and output signals at ECM Trouble Symptom 5 Trouble symptomProbable causeRemedyCannot decelerate (coast) by using the "SET/–" switchTemporary damaged or disconnected wiring of "SET/–" switch input circuitRepair the harness or replace the "SET/–" switchMalfunction of the ECM signalsCheck input and output signals at ECM Trouble Symptom 6 Trouble symptomProbable causeRemedyCannot accelerate or resume speed by using the "RES/+" switchDamaged or disconnected wiring, or short circuit, or "RES/+" switch input circuitRepair the harness or replace the "RES/+" switchMalfunction of the ECM signalsCheck input and output signals at ECM Trouble Symptom 7 Trouble symptomProbable causeRemedyCC system can be set while driving at a vehicle speed of less than 40km/h (25mph), or there is no automatic cancellation at that speedMalfunction of the vehicle-speed sensor circuitRepair the vehicle speed sensor system, or replace the partMalfunction of the ECM signalsCheck input and output signals at ECM Trouble Symptom 8 Trouble symptomProbable causeRemedyThe cruise main switch indicator lamp does not illuminate (But CC system is normal)Damaged or disconnected bulb of cruise main switch indicator lampRepair the harness or replace the part...