Engine Electrical System > Cruise Control System > P0568 Cruise Control Set Signal

General Description

The cruise control system keeps the vehicle running at a fixed speed until a signal canceling this fixed speed is received. When the main switch is turned on with vehicle in the running mode, the battery voltage is applied to the PCM. When a signal from the control switch is input to the PCM while the vehicle is in state,the PCM controls the ETS motor to make a car go at a steady speed you want. Also, while the system is operating, "CRUISE" indicator lamp in the meter assembly lights up.

DTC Description

If the SET swich signal is switching too frequently or stuck for too long, PCM sets P0568.

DTC Detecting Condition

Item

Detecting Condition

Possible Cause

DTC Strategy

•	Monitors the switch is switching too frequently or stuck for too long.

•	Poor connection

•	Faulty cruise switch

•	Faulty PCM

Enable Conditions

•	Engine is running

•	Ignition voltage ≥ 9V

•	Cruise control system type is learned

Threshold Value

•	Input switch signal is switching too frequently or stuck

Diagnosis Time

•	Switching: more than 1 second failure for 300 seconds test

•	Stuck: more than 75 seconds failure for 300 seconds test

MIL On Condition

•	NO MIL ON(DTC only)

Specification

Item	Resistance(Ω)
ON/OFF switch	3.9 kΩ ± 5％
SET switch	220 Ω ± 5%
RESUME switch	910 Ω ± 5%
CANCEL switch	0 Ω ± 5%

Schematic Diagram

Monitor Dtc Status

1.	Connect scantool to Data Link Connector(DLC).

IG "ON".

3.	Select "DTC" button, and then Press "DTC Status" to check DTC's information from the DTCs menu.

4.	Read "DTC Status" parameter.

Is parameter displayed "Present fault"?

	▶ Go to "Terminal and Connector inspection" procedure.
	▶ Fault is intermittent caused by poor contact in the sensor's and/ or PCM's connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection, ending, corrosion, contamination, deterioration, or damage. Repair or eplace as necessary and go to "Verification of vehicle Repair" procedure.

Terminal And Connector Inspection

1.	Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.

2.	Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.

Has a problem been found?

	▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure
	▶ Go to " Component Inspection " procedure.

Component Inspection

Check Auto Cruise Switch

1.	IG "OFF" and disconnect Cruise switch connector.

Measure resistance between signal and ground terminals of Cruise switch connector with "SET" switch depressed.(Component side)

Specification :

Item	Resistance(Ω)
SET switch	220 Ω ± 5% between signal and ground terminals

Is the measured resistance within specification?

	▶ Substitute with a known - good PCM and check for proper operation. If the problem is corrected, replace PCM and go to "Verification of Vehicle Repair" procedure.
	▶ Substitute with a known - good auto cruise switch and check for proper operation. If the problem is corrected, replace auto cruise switch and go to "Verification of Vehicle Repair" procedure.

There is a memory reset function on scantool that can erase optional parts automatically detected and memorized by PCM.

After testing PCM on the vehicle, use this function to reuse the PCM on the others

Verification Of Vehicle Repair

After a repair, it is essential to verify that the fault has been corrected.

1.	Connect scantool and select "DTC" button.

2.	Press "DTC Status" button and confirm that "DTC Readiness Flag" indicates "Completed". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions.

3.	Read "DTC Status" parameter.

Is parameter displayed "History(Not Present) fault"?

	▶ System performing to specification at this time. Clear the DTC.
	▶ Go to the applicable troubleshooting procedure.