P0125

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

While the engine is warming, the PCM monitors the ECT sensor to determine how long it takes the engine to reach the coolant temperature required for Closed Loop operation. DTC P0125 will set if the PCM determines that the engine does not reach Closed Loop temperature in a specified amount of time. This test will not run if either the intake air or engine coolant temperature is too low at start up. The PCM will only run this DTC on a cold start and only once per cold start.

CONDITIONS FOR SETTING THE DTC

^ DTCs P0112, P0113, P0117, P0118, not set.

^ Engine coolant and intake air temperature are greater than 10°C (50°F) at start-up.

^ Vehicle speed greater than 8 km/h (5 mph).

^ Closed loop coolant temperature, 60°C (140°F), is not reached within about 7 minutes.

ACTION TAKEN WHEN THE DTC SETS

^ The PCM will illuminate the Malfunction Indicator Lamp (MIL) on the second consecutive drive trip that the diagnostic runs and fails.

^ The PCM will record operating conditions at the time the diagnostic fails. The first time the diagnostic fails, this information will be stored in Failure Records. If the diagnostic reports a failure on the second consecutive drive trip, the operating conditions at the time of failure will be written to Freeze Frame and the Failure record will be updated.

CONDITIONS FOR CLEARING THE MIL/DTC

^ The PCM will turn the MIL OFF after three consecutive drive trips that the diagnostic runs and does not fail.

^ A last test failed (Current DTC) will clear when the ignition is cycled and the diagnostic runs and does not fail.

^ A History DTC will clear after forty consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.

^ PCM battery voltage is interrupted. Using a Scan tool.

DIAGNOSTIC AIDS

^ Using Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If the DTC cannot be duplicated, the information included in the Freeze Frame and/or Failure Records data can be useful in determining how many miles since the DTC set. The Fail Counter and Pass Counter can also be used to determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that were noted. This will isolate when the DTC failed. For intermittents, refer to Symptoms. Testing and Inspection

^ If other DTCs are set that share the same ground and/or 5.0 volt reference circuit, check for faulty connections and for faulty wiring.

^ If the engine has been allowed to sit overnight, the engine coolant temperature and intake air temperature values should display within a few degrees of each other. If the temperatures are not within 3°C (5°F), refer to Temperature Vs Resistance Table.

^ If it is determined that the DTC occurs intermittently, performing the P1114 or P1115 diagnostics table may isolate the cause of the fault.

^ If the engine coolant temperature exceeds 60°C (140°F), this indicates that the engine is capable of reaching the proper temperature, but not necessarily in the correct amount of time.

This diagnostic table must be repeated on a cold engine, engine coolant and intake air temperature less than 50°C (122°F) and within 3°C (5°F) of each other, and the time required to reach the temperature threshold must be measured. When starting a cold engine, measure the amount of time it takes the engine to reach the specified temperature. The engine should reach the specified temperature within 7 minutes. If the specified temperature is not reached within 7 minutes, check the following:

^ Coolant level.

^ Thermostat operation.

^ Are fans on at all times?

^ Refer to Engine Cooling System for additional information.

TEST DESCRIPTION

Number(s) below refer to step numbers on the diagnostic table.

2. An ECT failure could cause a DTC P0125 to set, so correct any ECT DTCs that are set. For any test that requires probing the PCM or a component harness connector, must use the Connector Test Adapter Kit J 35616-A. Using this kit will prevent damage to the harness connector terminals.

6. If it is obvious that the engine is not reaching full operating temperature, for example the radiator hoses never get very warm, or there is a complaint of little or no heat from the heater, this step could be skipped.