Hyundai Sonata: General Information / Troubleshooting

Hyundai Sonata LF 2014-2019 Service Manual / Engine Electrical System / General Information / Troubleshooting

Troubleshooting

Ignition System

Symptom	Suspect Area	Remedy
Engine will not start or is hard to start (Cranks OK)	Ignition lock switch	Inspect ignition lock switch, or replace as required
	Ignition coil	Inspect ignition coil, or replace as required
	Spark plugs	Inspect spark plugs, or replace as required
	Ignition wiring disconnected or broken	Repair wiring, or replace as required
Rough idle or stalls	Ignition wiring	Repair wiring, or replace as required
Rough idle or stalls	Ignition coil	Inspect ignition coil, or replace as required
Engine hesitates/poor acceleration	Spark plugs and spark plug cables	Inspect spark plugs / cable, or replace as required
Engine hesitates/poor acceleration	Ignition wiring	Repair wiring, or replace as required
Poor mileage	Spark plugs and spark plug cables	Inspect spark plugs / cable, or replace as required

Charging System

Symptom	Suspect Area	Remedy
Charging warning indicator does not light with ignition switch "ON" and engine off.	Fuse blown	Check fuses
	Light burned out	Replace light
	Wiring connection loose	Tighten loose connection
	Electronic voltage regulator	If light turns off, replace voltage regulator.
Charging warning indicator does not go out with engine running. (Battery requires frequent recharging)	Drive belt loose or worn	Adjust belt tension or replace belt
	Battery cable loose, corroded or worn	Inspect cable connection, repair or replace cable
	Electronic voltage regulator or alternator	If light turns off, replace voltage regulator or alternator
	Wiring	Repair or replace wiring
Overcharge	Electronic voltage regulator	If light turns off, replace voltage regulator.
Overcharge	Voltage sensing wire	Repair or replace wiring
Discharge	Drive belt loose or worn	Adjust belt tension or replace belt
	Wiring connection loose or short circuit	Inspect wiring connection, repair or replace wiring
	Electronic voltage regulator or alternator	If light turns off, replace voltage regulator or alternator
	Poor grounding	Inspect ground or repair
	Worn battery	Replace battery

Starting System

Symptom	Suspect Area	Remedy
Engine will not crank	Battery charge low	Charge or replace battery
	Battery cables loose, corroded or worn out	Repair or replace cables
	Transaxle range switch (Vehicle with automatic transaxle only)	Refer to AT group-automatic transaxle
	Fuse blown	Replace fuse
	Starter motor faulty	Replace
	Ignition switch faulty	Replace
Engine cranks slowly	Battery charge low	Charge or replace battery
	Battery cables loose, corroded or worn out	Repair or replace cables
	Starter motor faulty	Replace
Starter keeps running	Starter motor faulty	Replace
Starter keeps running	Ignition switch	Replace
Starter spins but engine will not crank	Short in wiring	Repair or replace wiring
	Pinion gear teeth broken or starter motor	Replace
	Ring gear teeth broken	Replace fly wheel or torque converter

Special Service Tools

Special Service Tools Tool (Number and name)IllustrationUse09373-27000Alternator pulley remover wrenchRemoval and installation of alternator pulley 09964-C1100SCC reflectorReflector to a ...

Other information:

Hyundai Sonata LF 2014-2019 Service Manual: Alternator Schematic Diagrams
Circuit Diagram • COM signal - When controlling the voltage generated, the ECM sends the target voltage data to the alternator via a PWM signal.(High voltage: 4V or higher, low voltage: 2V or lower) • FR signal - The transistor activation signal inside t ...

Hyundai Sonata LF 2014-2019 Owners Manual: Air bag inflation conditions
Front air bags Front air bags and the driver's knee air bag are designed to inflate in a frontal collision depending on the severity, speed, or angles of impact of the front collision. Side and curtain air bags Side and curtain air bags are designed to inflate when an impact is detected by side ...