DESCRIPTION
The cruise control system consists of an accelerator switch (automatic transaxle) or clutch switch (manual transaxle), actuator, main switch, vehicle speed sensor, operator control switches, brake switch and electronic control unit (ECU) with self-diagnostic function.
The accelerator switch is located on a bracket above accelerator pedal. The clutch switch is located on clutch pedal bracket. The actuator is mounted on passenger side shock tower. The main switch is located on dash to right of instrument cluster. The vehicle speed sensor is located on back side of instrument cluster. The operator controls are located on right steering column stalk. Sonata ECU is located under left side of dash. ECU is on passenger side kick panel on Elantra and Scoupe.
ACTUATOR
The motorized actuator controls throttle valve through a series of cables and intermediate pulleys. Pulleys are mounted as an assembly on right side of firewall and actuator is mounted on right side shock tower.
ELECTRONIC CONTROL UNIT (ECU)
The ECU incorporates circuitry which provides set, coast, resume, acceleration, cancel, low-speed limitation, overdrive OFF control and automatic cancellation functions. The ECU inputs signals from vehicle speed sensor and switches, and outputs control signals to actuator's DC motor, electromagnetic clutch, automatic transaxle control unit and the alarm. The self-diagnostic function will store codes only as long as ignition and cruise control main switch remains on.
CONTROL SWITCH
See STEERING COLUMN SWITCHES article in the ACCESSORIES/SAFETY EQUIPMENT Section.
EQUIPMENT HOOKUP
Connect Multi-Use Tester (09391-33100 for Elantra or 09391-33000 for all other models), to vehicle diagnostic connector and lighter socket. Connector is located near fuse box on driver's kick panel. (Scheme 1) Follow manufacturer's operating instructions.
Alternatively a voltmeter can be used. Connect as shown. (Scheme 1) Proceed to READING CODES.
Scheme 1
Note. When ECU power supply (ignition switch and/or main switch) is turned off, diagnostic codes will be erased.
READING CODES
Trouble codes are displayed on voltmeter as a series of voltages pulses. Display of trouble codes will start when vehicle speed decreases to 12 MPH (20 KM/H), after cancellation of system and continue as long as main switch and ignition switch remain on. Example: Code 23 would be displayed as 2 long pulses followed by 3 short pulses followed by a 3 second pause. (Scheme 2)
Scheme 2
Normal
Displayed as a series of 0.5 second pulses.
Code 11
Could be caused by an open transistor, open brake circuit, blown fuse, brakelight switch closed or brakelight circuit open.
Code 12
Indicates that signal from vehicle speed sensor has not been received for more than one second.
Code 13
Indicates low speed limiter activation. System is normal if it can be reset.
Code 14
Indicates cancellation activated by reduction of vehicle speed. System is normal if it can be reset.
Code 15
Indicates control switch malfunction (SET and RESUME switches ON simultaneously).
Code 16
Could be caused by open fuse or circuit in brakelight switch, auto transaxle neutral safety switch ON (closed), open in brakelight circuit or brakelight switch ON.
Note. Codes 21-25 are accessed with main, set and resume switches in ON position. Any code remaining after related switch is turned OFF, indicates a failure in selected switch or circuit.
Code 21
Set switch circuit normal.
Code 22
Resume switch circuit normal.
Code 23
Cancel switch circuits normal.
Code 24
Over 24 MPH (40 KM/H) speed sensor circuit normal.
Code 25
Under 24 MPH (40 KM/H) speed sensor circuit normal.
Disconnect actuator connector. Measure resistance of clutch coil between terminals No. 3 and 4. Resistance should be 55 ohms. If resistance is not as specified, replace actuator. (Scheme 3)or (Scheme 4).
Scheme 3
Scheme 4
BRAKELIGHT SWITCH
Check for continuity between terminal "C" and terminal "D" with switch plunger depressed. Check for continuity between terminal "A" and terminal "B" with switch plunger released. If switch does not test as described, replace switch. (Scheme 5)
Scheme 5
CLUTCH SWITCH
Ensure continuity exists when clutch switch plunger is depressed and no continuity exists when plunger is released. (Scheme 6)
Scheme 6
CRUISE CONTROL SWITCH TEST
See STEERING COLUMN SWITCHES article in the ACCESSORIES/SAFETY EQUIPMENT Section.
MAIN SWITCH TEST
Turn ignition switch on. Depress cruise control main switch and observe indicator lamp. If lamp comes on, switch is functioning properly. If lamp does not come on, fuse, wiring or switch for may be at fault.
NEUTRAL SAFETY SWITCH
Disconnect neutral safety switch connector. Ensure continuity exist between terminals No. 3 and 5 when shift lever is in "N" position and between terminals No. 3 and 4 when shift lever is in "P" position. Adjust or replace switch if not within specifications. (Scheme 7)
Scheme 7
SYSTEM CANCELS WHEN NOT WANTED
If system can be reset, try to duplicate symptom during test drive. If symptom reoccurs, check diagnostic codes with engine running and main switch on. If symptom does not reoccur, check whether or not vehicle was driven on steep slope, or SET and RESUME switches were operated at the same time. If system cannot be reset, go to next symptom check.
SYSTEM CANNOT BE SET
- Check ECU power supply circuit and SET and RESUME switch function. If fault is found, repair affected area. If no fault is found, check SET switch ON function. Replace control switch if defective. Check for SET switch input wire short. Repair harness if necessary.
- Check RESUME switch ON function and check input wire for short. Repair as necessary. Check each CANCEL circuit. Repair as necessary. Check vehicle speed sensor for malfunction. Repair or replace as necessary. Ensure actuator and circuit is functioning properly. If abnormal conditions are not found in actuator or actuator circuit, replace ECU.
SET SPEED VARIES (HUNTING)
Check vehicle speed sensor, speedometer cable and speedometer drive gear. Repair or replace as necessary. Check actuator circuit connections for poor contact. repair as necessary. Ensure actuator is functioning properly. Replace ECU if all items check okay.
SYSTEM WON'T CANCEL WITH BRAKE PEDAL APPLICATION
Check for damaged wiring or disconnected brakelight switch. Repair harness or replace brakelight switch as necessary. Check actuator drive circuit for short. Repair harness or replace actuator as necessary. Replace ECU if all items check okay.
SYSTEM WON'T CANCEL WITH CLUTCH PEDAL APPLICATION
It is canceled however, when brake pedal is depressed. Check for damaged wiring or disconnected clutch switch. Repair harness or replace clutch switch as necessary. Ensure clutch switch is installed properly and adjust as necessary. Replace ECU if all items check okay.
SYSTEM WON'T CANCEL WHEN SHIFTED INTO NEUTRAL
It will cancel, however, when brake pedal is depressed. Check for damaged wiring or disconnected neutral safety switch. Repair harness or replace switch as necessary. Check neutral safety switch for proper adjustment. Adjust as necessary. Replace ECU if all items check okay.
SYSTEM WON'T COAST USING SET SWITCH
Check for intermittent operation of SET switch circuit or switch. Repair or replace as necessary. Check actuator circuit for poor contact and proper operation. Repair or replace as necessary. Replace ECU if all items check okay.
SYSTEM WON'T ACCELERATE OR RESUME SPEED
Check for damaged or disconnected wiring, or short circuit in RESUME switch circuit. Repair or replace as necessary. Check actuator circuit for poor contact and proper operation. Repair or replace as necessary. Replace ECU if all items check okay.
SYSTEM CAN BE SET AT LESS THAN 25 MPH
Check vehicle speed sensor, speedometer cable and speedometer drive gear. Repair or replace as necessary. Check actuator circuit connections for poor contact. repair as necessary. Ensure actuator is functioning properly. Replace ECU if all items check okay.
MAIN INDICATOR LIGHT OFF BUT SYSTEM WORKS
Check for damaged or disconnected bulb of cruise control main switch. Check wiring for damage or disconnection. Repair or replace as necessary.
NO ALARM WHEN SET OR RESUME SWITCH IS USED
If system functions normally, check alarm and alarm circuit wiring. Repair or replace as necessary. Replace ECU if all items check okay.
OVERDRIVE NOT CANCELED AT FIXED SPEED OR NO SHIFT INTO OVERDRIVE
Check overdrive cancellation circuit for damaged wires or poor connections. Replace ECU if all items check okay.
WIRING DIAGRAMS
For 1992 model wiring diagrams, See appropriate chassis wiring diagram in the WIRING DIAGRAMS Section.
