4.
Check for ECT sensor signal at idle.
caution
If the output data changes as temperature changes,the sensor is good.
This is the inspection procedure to determine whether it is present DTC or memoried one by monitoring the current signal or by using the function of oscilloscope with Hi-scan pro.
Connect scan tool to DLC.
IG KEY : ON
Start engine and warm up to operating temperature.
Check for ECT sensor signal at idle.
If the output data changes as temperature changes,the sensor is good.
This inspection procedure is recommended when service data with scan tool in not enough.
Start engine and warm up to operating temperature.
Probe(+) : ECTS harness connector NO4.
Probe(-) : Chassis ground.
If the ECTS output is in inverse proportion to water temperature,the sensor is normal
Service standard
When ECT is 0℃ (32℉) : 3.7~4.3 V
When ECT is 20℃(68℉) : 3.2~3.6 V
When ECT is 40℃(104℉) : 2.4~3.05 V
When ECT is 80℃(176℉) : 1.0~1.5 V
Service standard
When ECT is 0℃ (32℉) : 3.7~4.3 V
When ECT is 20℃(68℉) : 3.2~3.6 V
When ECT is 40℃(104℉) : 2.4~3.05 V
When ECT is 80℃(176℉) : 1.0~1.5 V
This figure shows the waveform at terminal 4 of ECTS at idle rpm.
In case the voltage of ECTS is always 4V.
Possible cause : Open ground circuit Open inner circit of component
In case,when engine is cold,the voltage is below 0.5V
Possible cause :Short between ECM and sensor, Faulty ECM
ECTS output is in inverse proportion to water temperature changes. This figure shows the waveform at terminal 4 of ECTS at idle rpm.
In case the voltage of ECTS is always 4V.
Possible cause : Open ground circuit. Open inner circuit of component.
In case,when engine is cold,the voltage is below 0.5V
Possible cause :Short between ECM and sensor Faulfy ECM
If the output voltage moves in reverse direction while water temperature changes,the ECT sensor is normal.
In case there is no symptom and wrong data but DTC is shown
The problem may be intermittent so slightly shake the connector and harness vertically and horizontally to check if there is any data changes
If the data changes normally, the problem was intermittent so erase DTC and verify the same DTC reoccure.
Go to "Terminal and Connector inspection" procedure.
In case there is symptom and wrong data with DTC
Check open,short or connector’s connection for ECTS.
Check the deterioration of ECTS performance.
Go to "circuit inspection" procedure.
