P0198 ECU Internal Temp Sensor Fault

COMPONENT LOCATION

DESCRIPTION (P0198)

1. GENERAL DESCRIPTION
ETCM internal temperature sensor which is negative thermistor type is located in the ETCM. And it senses the internal temperature of ETCM.
2. DTC DESCRIPTION
If the output voltage of the ETCM internal temperature sensor is below 0.2V or above 4.9V for more than 60 seconds at idle, at starting or at driving, the ETCM judges this as a fault and DTC is set. In case of fail safe, ETCM sets the internal temperature of ETCM to 77℃at starting, at idle and at driving.

Item	Detecting Condition			Possible Cause
DTC Strategy	• Voltage monitoring			•Defective ETCM internal temperature sensor (Inside ETCM)
Enable Conditions	• At starting/At idle/At drving
Threshold Value	• Below 0.2V or above 4.9V
Diagnosis Time	• Above 60 sec.
Fail Safe	Fuel Cut	No	• At starting, at idle, at driving: 77℃
	Fuel Limit	No
	MIL	Off

MONITOR SCANTOOL DATA (P0198)

1. Connect scan tool to the self-diagnosis connector.
2. Warm up the engine to the normal operating temperature.
3. Turn the electrical equipment and air conditioner OFF.
4. Monitor “ETCM internal Temp.” parameter on the scan tool.

ETCM internal temperature sensor changes with fuel temperature and temperature around engine depending on DTC detecting condition.
In case of fail safe, be sure to check “ETCM internal temp.” displayed on the scan tool is 77℃.

※ Troubleshooting aids:
When DTC related to ETCM internal Temp. sensor built-in ETCM occurs, it is impossible to check circuit. Therefore, check ETCM internal Temp. sensor by comparing engine coolant temperature sensor with fuel temperature.

COMPONENT INSPECTION

(1) Turn the ignition OFF.
(2) Disconnect the ETCM connector(E20, C40).
(3) Connect the ETCM connector(E20, C40) approx. 5~10 minutes later.
(4) Connect scan tool and select “Diagnostic Trouble Codes(DTCs)” mode and then clear DTC.
(5) Drive the vehicle under conditions noted in failure records.

VERIFICATION OF VEHICLE REPAIR

After a repair, it is essential to verify that the fault has been corrected.
1. Connect scan tool and select “Diagnostic Trouble Codes(DTCs)” mode and then clear DTC.
2. Drive the vehicle under conditions noted in failure records.
3. Did the DTC return?