P0125

P0125 - Insufficient Coolant Temperature for Cosed Loop Fuel Control





Component Location




DTC Detecting Condition

NOTE: If any codes relating to ECTS, IATS circuits are present,do all repairs associated with those codes before proceeding with this troubleshooting procedure




Specification




Schematic Diagram




Signal Waveform


Monitor DTC Status

1. Connect scantool to Data Link Connector(DLC).
2. Warm up the engine to normal operating temperature.




3. Monitor the "ECTS signal" parameter on the scantool.


NOTE:

If the output data changes as temperature changes,the sensor is good
If the ECTS output is in inverse proportion to water temperature,the sensor is normal.

Service standard

When ECT is 0�C (32�F) : 4.27 +/- 0.3 V
When ECT is 20�C(68�F) : 3.44 +/- 0.3 V
When ECT is 40�C(104�F) : 2.72 +/- 0.3 V
When ECT is 80�C(176�F) : 1.25 +/- 0.3 V

4. Is parameter displayed within specifications?

YES
1) Fault is intermittent caused by poor contact in the sensor's and/or PCMs connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion,contamination,deterioration, or damage. Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.

NO
1) Go to "W/Harness Inspection" 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.

3. Has a problem been found?

YES
1) Repair as necessary and go to "Verification of vehicle Repair" procedure.

NO
1) Go to "Signal circuit inspection" procedure.


Signal Circuit Inspection

1. Check for open in harness

(1) Ignition "OFF"
(2) Disconnect ETC sensor connector.
(3) Ignition "ON" & Engine "OFF"




(4) Measure voltage between terminal 1 of sensor harness connector and chassis ground.

A. Specification : approximately 5V


(5) Is measure voltage within Specification?

YES
1) Go to "Check for short to power in harness " as below.

NO
1) In case over 5V : Short circuit to battery between ECTS harness connector and PCM harness connector.
In case 0V: Open circuit between ECTS harness connector and PCM harness connector. Repair as necessary and then go to "Verification of Vehicle Repair" procedure.


NOTE:

In case,when ECTS connector is disconnected,the voltage at terminal 1 is 0V.
>Possible cause : Open or short between Terminal 1 of ETCS connector and terminal 39 of PCM.


2. Check for short to power in harness

(1) Ignition "OFF"
(2) Disconnect ECT sensor connector and PCM connector.
(3) Ignition "ON" & Engine "OFF"




(4) Measure resistance between terminal 1 and 3 of sensor harness connector.

A. Specification : infinite



(5) Is measure resistance within Specification?

YES
1) Go to "Ground Circuit Inspection" procedure.

NO
1) Short circuit between cluster signal circuit and ECTS signal circuit. Repair as necessary and then go to "Verification of Vehicle Repair" procedure.



Ground Circuit inspection

1. Ignition "OFF"
2. Disconnect ECT sensor connector.
3. Ignition "ON" & Engine "OFF"




4. Measure voltage or resistance between terminal 2 of sensor harness connector and chassis ground.

A. Specification : below 0.5V or below 1 ohm

5. Is measure voltage or resistance within Specification?

YES
1) Go to "Component Inspection" procedure.

NO
1) Open circuit between ECTS harness connector and PCM harness connector. Open circuit between PCM harness connector and chassis ground. Repair as necessary and then go to "Verification of Vehicle Repair" procedure.


NOTE:

In case,when measuring resistence of ground circuit,the resistence is over 1 ohm.
>Possible cause : Short circuit between ECM ground point and PCM terminal 35.



Component Inspection

1. Cooling System inspection

(1) Check cooling system coolant level and fill if low.
(2) Check for a proper cooling system operation. Especially check that cooling and condenser fan working normally.
(3) Remove the thermostat and check the following items:

1) Stuck or damaged Full open lift : 8.5mm(0.33 in) or more
2) Verify the temperature at which the valve begins to open.Initial valve opening temperature : 82�C(179.6�F) Full valve opening temperature : 95�C(203�F)

(4) Is a problem found?

YES
1) Repair as necessary and go to "Verification vehicle Repair" procedure.

NO
1) Go to "Check ECTS" as below.



2. Check ECTS




(1) Measure resistance between terminal 1 and 2 of sensor connector(To sensor side)

A. Specification :

20�C(68�F) : 2.27~2.73k ohms
80�C(176�F) : 0.29~0.32k ohms



(2) Does each resistance indicate continuity circuit?

YES
1) Go to "Check PCM" as below.

NO
1) Open circuit ECTS. Repair as necessary and then go to "Verification of Vehicle Repair" procedure.



3. Check PCM. The purpose of checking ECM is to determine whether there is any malfunction of PCM .

(1) Ignition "OFF"
(2) Connect Scantool and Engine "ON "
(3) Select simulation function on scantool.
(4) Simulate voltage at terminal 1 of ECT sensor signal connector.




(5) Verify ECTS voltage to change while raising or lowering simulation voltage with scan tool within 0.5~3.5 V

A. Specification : If the data is changeable as simulation voltage changes, it's OK



(6) Is ECT sensor signal value changed according to simulation voltage ?

YES
1) Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.

NO
1) Substitute with a known-good PCM and check for proper operation. If the problem is corrected, replace PCM and then go to "Verification of Vehicle Repair" procedure.


Verification of Vehicle Repair

1. Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code (DTC) which has been diagnosed.
2. Using a Scantool, Clear the DTCs.
3. Operate the vehicle within conditions noted in the freeze frame data or enable conditions.
4. Monitor that all readiness test have been verified as "Complete"
5. Are any DTCs present ?

YES
1) Go to the applicable troubleshooting procedure.

NO
1) System is performing to specification at this time.