P0125
DTC P0125 INSUFFICIENT COOLANT TEMPERATURE FOR CLOSED LOOP FUEL CONTROLComponent Location:
COMPONENT LOCATION
GENERAL DESCRIPTION
An Engine Coolant Temperature Sensor (ECTS) monitors the temperature of the coolant. This input is used by the PCM for engine control and as an enabling criteria for same diagnostics. The air flow coming into the engine is accumulated and used to determine if the engine has been driven within conditions that would allow the engine coolant to heat up normally to the thermostat regulating temperature. If the coolant temperature does not reach regulating temperature of the thermostat, diagnostics that use the engine coolant temperature as enabling criteria may not run when expected.
DTC DESCRIPTION
If the coolant temperature does not reach the specified value within the established time parameters, the PCM determines that a malfunction exists and a DTC is stored.
DTC Detecting Condition:
Schematic Diagram:
Signal Waveform & Data:
MONITOR SCANTOOL DATA
1. Engine "ON"
2. Monitor Engine Coolant Temperature Sensor parameter on Current data.
3. After the engine has been starting, Check that ECT rises steady to about 90 °C (194 °F) and ECT stabilizes when the thermostat opens.
Specification: ECT rises steady to about 90 °C (194 °F) and ECT stabilizes when the thermostat opens. (Error range is 2 - 3%)
4. Is Current data displayed correctly?
YES: 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, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.
NO: Go to "System Inspection" procedure.
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. Has a problem been found?
YES: Repair as necessary and go to "Verification of Vehicle Repair" procedure.
NO: Go to "Component Inspection" procedure.
COMPONENT INSPECTION
1. Check ECTS
1. Ignition "OFF"
2. Disconnect ECTS connector.
3. Measure resistance between terminals 1 and 3 of the ECT sensor (to ECT sensor side).
Specification Error range is 2 - 3%
4. Is the measured resistance within specifications?
YES: Go to "Check PCM" as below.
NO:
- Substitute with a known - good ECTS and check for proper operation.
- If the problem is corrected, replace ECTS and go to "Verification of Vehicle Repair" procedure.
2. Check PCM
1. Ignition "OFF"
2. Connect Scantool and Ignition "ON"
3. Select simulation function on scantool.
4. Simulate voltage at terminal 1 of ECT sensor signal connector.
5. Does the signal value of ECT sensor changes according to simulation voltage?
YES: Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.
NO: 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.
VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verify that the fault has been corrected.
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 tests have been verified as "Complete"
5. Are any DTCs present?
YES: Go to the applicable troubleshooting procedure.
NO: System is performing to specification at this time.