Kia Optima: Troubleshooting - Cruise Control System - Engine Electrical SystemKia Optima: Troubleshooting

Trouble Symptom Charts
Trouble Symptom 1

Trouble Symptom 2


Trouble Symptom 2
Trouble symptom
Probable cause
Remedy
The set vehicle speed varies greatly upward or downward
"Surging" (repeated alternating acceleration and deceleration) occurs after setting
Malfunction of the vehicle speed sensor circuit
Repair the vehicle speed sensor system, or replace the part
Malfunction of brake system
Check input and output signals at brake system

Trouble Symptom 3
Trouble symptom
Probable cause
Remedy
The CC system is not canceled when the brake pedal is depressed
Damaged or disconnected wiring of the brake pedal switch or malfunction of the brake stroke sensor or circuit
Repair the harness or replace the brake pedal switch
Malfunction of the brake signals or brake system
Check input and output signals at HCU or brake system

Trouble Symptom 4
Trouble symptom
Probable cause
Remedy
The 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 circuit
Repair the harness or repair or replace the inhibitor switch
Improper adjustment of inhibitor switch
Malfunction of the TCU signals
Check input and output signals at TCU

Trouble Symptom 5
Trouble symptom
Probable cause
Remedy
Cannot decelerate (coast) by using the "SET/–" switch
Temporary damaged or disconnected wiring of "SET/–" switch input circuit
Repair the harness or replace the "SET/–" switch
Malfunction of the cluster signals
Check input and output signals at cluster

Trouble Symptom 6
Trouble symptom
Probable cause
Remedy
Cannot accelerate or resume speed by using the "RES/+" switch
Damaged or disconnected wiring, or short circuit, or "RES/+" switch input circuit
Repair the harness or replace the "RES/+" switch
Malfunction of the cluster signals
Check input and output signals at cluster

Trouble Symptom 7
Trouble symptom
Probable cause
Remedy
CC system can be set while driving at a vehicle speed of less than 40km/h (25mph), or there is no automatic cancellation at that speed
Malfunction of the vehicle-speed sensor circuit
Repair the vehicle speed sensor system, or replace the part
Malfunction of the brake system
Check input and output signals at brake system

Trouble Symptom 8
Trouble symptom
Probable cause
Remedy
The cruise main switch indicator lamp does not illuminate (But CC system is normal)
Damaged or disconnected bulb of cruise main switch indicator lamp
Repair the harness or replace the part.
Harness damaged or disconnected

Schematic Diagrams
System Block Diagram Component Parts And Function Outline Component partFunctionECUControls engine.MCUControls drive motor.ABSSends vehicle speed to HCU.HCUReceives signals from sensor and contr ...

Cruise Control Switch Schematic Diagrams
Circuit Diagram ...

See also:

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Side Airbag (SAB) Module Repair procedures
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