P0125

CIRCUIT DESCRIPTION
An engine coolant temperature (ECT) sensor monitors the temperature of the coolant. This input is used by the powertrain control module (PCM) for engine control and as an enabling criteria for some 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 increase normally or does not reach regulating temperature of the thermostat, diagnostics that use engine coolant temperature as enabling criteria, may not run when expected.

This diagnostic trouble code (DTC) will only run once per ignition cycle within the enabling conditions.

This DTC will set when there has been excessive time to reach a minimum coolant temperature required for Closed Loop fuel control.

CONDITIONS FOR RUNNING THE DTC
^ DTCs P0110, P0111, P0112, P0113, P0116, P0117, P0118, P0128, P1114, or P1115 are not set.
^ The minimum air temperature is more than -7°C (19°F).
^ The start up engine coolant temperature (ECT) is below 40°C to +40°C (-40°F to +104°F).

CONDITIONS FOR SETTING THE DTC
^ The engine run time is more than 5 minutes, in order to achieve a Closed Loop temperature of -10°C (+14°F).
^ The calibrated amount of air flow has been exceeded.
^ The maximum idle time has been less than 4 minutes.

DIAGNOSTIC AIDS
DTC P0125 is designed to detect a skewed ECT sensor.

If a DTC P0125 and a P0128 are set a faulty thermostat may be the cause (manual transmission).

TEST DESCRIPTION

Steps 1-3:

Steps 4-11:

The numbers below refer to the step numbers on the diagnostic table.
3. This step tests for excessive resistance in the ECT circuit.
7. This step tests for a skewed sensor through the range of temperatures affecting this DTC.