DTC P0125 Engine Coolant Temperature
(ECT) Excessive
The PCM monitors the ECT
sensor in order to determine how long it takes the engine to reach the coolant
temperature required for Closed Loop operation. DTC P0125 sets 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 Running the DTC
- DTCs P0112, P0113, P0117, P0118 not
set
- The engine is operating.
- The engine coolant temperature is
between -36°C (-33°F) and 40°C (104°F) at engine start-up.
- The intake air temperature is
greater than -7°C (19°F).
- The vehicle speed is greater than
1.6 km/h (1 mph).
Conditions
for Setting the DTC
The closed loop coolant
temperature of 34°C (93°F) is not reached within a predetermined time. The
maximum allowable time depends on the start-up coolant temperature and the
amount of airflow into the engine. The range for the time is from 2 minutes and
20 seconds to 22 minutes and 30 seconds.
Action
Taken When the DTC Sets
- The PCM illuminates the malfunction
indicator lamp (MIL) on the second consecutive ignition cycle that the
diagnostic runs and fails.
- The PCM records the operating
conditions at the time the diagnostic fails. The first time the diagnostic
fails, the PCM stores this information in the Failure Records. If the
diagnostic reports a failure on the second consecutive ignition cycle, the
PCM records the operating conditions at the time of the failure. The PCM
writes the conditions to the Freeze Frame and updates the Failure Records.
Conditions
for Clearing the MIL/DTC
- The PCM turns OFF the malfunction
indicator lamp (MIL) after 3 consecutive ignition cycles that the
diagnostic runs and does not fail.
- A last test failed, or current DTC,
clears when the diagnostic runs and does not fail.
- A history DTC clears after
40 consecutive warm-up cycles, if no failures are reported by this or
any other emission related diagnostic.
- Use a scan tool in order to clear
the MIL and the DTC.
Important
- Remove any debris from the PCM connector surfaces
before servicing the PCM. Inspect the PCM connector gaskets when
diagnosing/replacing the PCM. Ensure that the gaskets are installed
correctly. The gaskets prevent contaminate intrusion into the PCM.
- For any test that requires probing the PCM or component
harness connectors, use the Connector Test Adapter Kit J 35616-A .
Using this kit prevents any damage to the harness connector terminals.
- Using the Freeze Frame and/or
Failure Records data may aid in locating an intermittent condition. If you
cannot duplicate the DTC, the information included in the Freeze Frame
and/or Failure Records data can help determine how many miles since the
DTC set. The Fail Counter and Pass Counter can also help determine how
many ignition cycles the diagnostic reported a pass and/or a fail. Operate
the vehicle within the same freeze frame conditions (RPM, load, vehicle
speed, temperature etc.) that you observed. This will isolate when the DTC
failed.
- If the engine has sat 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 .
- If you determine that the DTC occurs
intermittently, performing the P1114 or P1115 diagnostics table may
isolate the cause of the fault.
- An engine coolant temperature
exceeding 34°C (93°F), indicates that the engine
is capable of reaching the proper temperature, but not necessarily in the
correct amount of time. Repeat this diagnostic table on a cold engine, and
measure the time required to reach the temperature threshold. 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 5 minutes or less. If the engine does not reach the
specified temperature within 5 minutes, inspect the following:
- Coolant level. Refer to Draining
and Filling Cooling System in Engine Cooling.
- Thermostat operation. Refer to Thermostat
Diagnosis in Engine Cooling.
- Are the fans on at all times? Refer
to Electric
Cooling Fan Diagnosis .
- For an intermittent condition, refer
to Symptoms
.
The numbers below refer
to the step numbers on the diagnostic table.
- 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, use
the Connector Test Adapter Kit J 35616-A .
Using this kit prevents damage to the harness connector terminals.
|
Step |
Action |
Value(s) |
Yes |
No |
|
Did
you perform the Powertrain On-Board Diagnostic
(OBD) System Check? |
-- |
|||
|
Are any engine coolant temperature DTCs set? |
-- |
Go to applicable DTC
table |
||
Does
scan tool indicate the ECT sensor is less than the specified value? |
-35°C (-31°F) |
Go to DTC
P0117 Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage |
||
|
Jumper
the terminals of the ECT sensor harness connector together using a jumper
wire. Does the scan tool indicate the ECT is greater than the specified
value? |
139°C (282°F) |
Go to DTC
P0118 Engine Coolant Temperature (ECT) Sensor Circuit High Voltage |
||
Important Allow the engine to warm up
if it has not already reached the specified temperature. 5 minutes is the
maximum amount of time it should take to reach this temperature from a cold
start. Less time is required if the engine is already warm. Does
the scan tool indicate the engine coolant temperature reached the specified
value? |
34°C (93°F) |
The cooling system
must be retested on a cold start. Go to Diagnostic Aids. |
||
|
Measure
the resistance of the ECT sensor using the DMM J 39200 .
Refer to Temperature vs Resistance . Is the ECT resistance close to
the value indicated in the Temperature Vs Resistance Table? |
-- |
|||
|
Inspect
the following for an engine cooling system condition:
Is
the action complete? |
-- |
-- |
||
|
Replace
the ECT sensor. Refer to Engine
Coolant Temperature (ECT) Sensor Replacement . Is the action complete? |
-- |
-- |
||
Does
the scan tool indicate that this test failed? |
-- |
|||
|
Select
the Capture Info option and the Review Info option using the scan tool. Does
the scan tool display any DTCs that you have not diagnosed? |
-- |
Go to the applicable
DTC table |
System OK |