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Chrysler Sebring, Stratus sedan, Sebring Convertible. Manual - part 176

Symptom:

P0125-INSUFFICIENT COOLANT TEMP FOR CLOSED-LOOP FUEL
CONTROL

When Monitored and Set Condition:

P0125-INSUFFICIENT COOLANT TEMP FOR CLOSED-LOOP FUEL CONTROL

When Monitored:

With battery voltage greater than 10.4 volts, after engine is started.

Set Condition:

The engine temperature does not enable closed loop. Failure time depends

on start-up coolant temperature and ambient temperature. (i.e. 2 minutes for a start temp
of 10°C (50°F) or up to 10 minutes for a vehicle with a start-up temp of -28°C (-18°F). Two
Trip Fault.

POSSIBLE CAUSES

LOW COOLANT LEVEL

THERMOSTAT OPERATION

ENGINE COOLANT TEMPERATURE SENSOR

TEST

ACTION

APPLICABILITY

NOTE: If a Engine Coolant Temperature (ECT) DTC is set along with this
code, diagnose the ECT DTC first.
NOTE: Inspect the ECT terminals and related PCM terminals. Ensure the
terminals are free from corrosion and damage.
NOTE: The best way to diagnose this DTC is to allow the vehicle to sit
overnight outside in order to have a totally cold soaked engine.
Note: Extremely cold outside ambient temperatures may have caused this
DTC to set.
WARNING: Never open the cooling system when the engine is hot. The
system is under pressure. Extreme burns or scalding may result. Allow the
engine to cool before opening the cooling system.
Check the coolant system to make sure that the coolant is in good condition and at
the proper level.
Is the coolant level and condition OK?

All

Yes

→ Go To 2

→ Inspect the vehicle for a coolant leak and add the necessary

amount of coolant.
Perform POWERTRAIN VERIFICATION TEST VER - 5.

DRIVEABILITY - NGC

TEST

ACTION

APPLICABILITY

NOTE: This test works best if performed on a cold engine (cold soak).
Ignition on, engine not running.
With the DRBIII

t, read the ECT Deg value. If the engine was allowed to sit overnight

(cold soak), the temperature value should be a sensible value that is somewhere close
to the ambient temperature.
Note: If engine coolant temperature is above 82°C (180°F), allow the engine
to cool until 65°C (150°F) is reached.
Start the Engine.
During engine warm-up, monitor the ECT Deg value. The temp deg value change
should be a smooth transition from start up to normal operating temp 82°C (180°F)
. Also monitor the actual coolant temperature with a thermometer.
NOTE: As the engine warms up to operating temperature, the actual coolant
temperature (thermometer reading) and the ECT Deg in the DRB sensor
should stay relatively close to each other.
Using the appropriate service information, determine the proper opening tempera-
ture of the thermostat.
Did the thermostat open at the proper temperature?

All

Yes

→ Go To 3

→ Replace the thermostat.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

Ignition on, engine not running.
With the DRBIII

t, read the ECT Sensor temperature value. If the engine was

allowed to sit overnight (cold soak), the temperature value should be a sensible value
that is somewhere close to the ambient temperature.
Note: If engine coolant temperature is above 82°C (180°F), allow the engine
to cool until 65°C (150°F) is reached.
Start the Engine.
During engine warm-up, monitor the ECT Deg value. The temp deg value change
should be a smooth transition from start up to normal operating temp 82°C (180°F)
. Also monitor the actual coolant temperature with a thermometer.
NOTE: As the engine warms up to operating temperature, the actual coolant
temperature (thermometer reading) and the ECT Sensor Temperature in
the DRBIII

t sensors should stay relatively close to each other.

Is the thermometer reading relatively close to the DRBIII

t ECT Sensor reading?

All

Yes

→ Test Complete.

→ Replace the Engine Coolant Temperature Sensor.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

DRIVEABILITY - NGC

P0125-INSUFFICIENT COOLANT TEMP FOR CLOSED-LOOP FUEL CON-
TROL —

Continued

Symptom:

P0128-THERMOSTAT RATIONALITY

When Monitored and Set Condition:

P0128-THERMOSTAT RATIONALITY

When Monitored:

The engine running. During cold start.

Set Condition:

The PCM predicts a coolant temperature value that it will compare to the

actual coolant temperature. If the two coolant temperature values are not within 10°C
(50°F) of each other an error is detected. Two Trip Fault.

POSSIBLE CAUSES

GOOD TRIP EQUAL TO ZERO

LOW COOLANT LEVEL

OTHER POSSIBLE CAUSES

SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE

MONITOR ENGINE COOLANT TEMPERATURE

TEMPERATURE SENSOR VOLTAGE BELOW 1.0 VOLT

SIGNAL CIRCUIT OPEN

SENSOR GROUND CIRCUIT OPEN

SIGNAL CIRCUIT SHORTED TO GROUND

SIGNAL CIRCUIT SHORTED TO SENSOR GROUND

PCM LOW

PCM HIGH

TEST

ACTION

APPLICABILITY

NOTE: If any ECT, AAT, CMP or CKP sensor DTCs have set along with P0128,
diagnose them first before continuing.
NOTE: Ensure that Pinion Factor has been programmed correctly into the
PCM.
Ignition on, engine not running.
With the DRBIII

t, read DTCs and record the related Freeze Frame data.

Is the Good Trip displayed and equal to zero?

All

Yes

→ Go To 2

→ Refer to the INTERMITTENT CONDITION symptom in the

Driveability category.
Perform POWERTRAIN VERIFICATION TEST VER - 5.

DRIVEABILITY - NGC

TEST

ACTION

APPLICABILITY

All

Yes

→ Go To 3

→ Inspect the vehicle for a coolant leak and add the necessary

amount of coolant.
Perform POWERTRAIN VERIFICATION TEST VER - 5.

Using the appropriate service information, determine the proper opening tempera-
ture of the thermostat.
NOTE: It is important that the thermostat meets all OEM specifications. An
incorrect thermostat or an improperly installed thermostat will cause this
DTC to set.
NOTE: This test works best if performed on a cold engine (cold soak).
Ignition on, engine not running.
With the DRBIII

t, monitor the Engine Coolant temperature. If the engine was

allowed to sit overnight (cold soak), the temperature value should be a sensible value
that is somewhere close to the ambient temperature.
NOTE: If engine coolant temperature is above 82°C (180°F), allow the engine
to cool until 65°C (150°F) is reached.
Start the Engine.
During engine warm-up, monitor the ECT Deg value on the DRBIII

t. The temper-

ature change should be a smooth transition from start up to normal operating temp
82°C (180°F) . Also monitor the actual coolant temperature with a thermometer.
NOTE: As the engine warms up to operating temperature, the actual coolant
temperature (thermometer reading) and the ECT Deg on the DRBIII

should stay within 10° (18°F) of each other.
If the thermostat does not open at the proper temperature, replace the thermostat.
If the monitored Engine Coolant Temperature transition from cold to hot was not
smooth or if the temperature value on the DRBIII

t was not within 10°C (18°F) of the

thermometer reading during warm-up, replace the ECT Sensor.
Were any problems found?

All

Yes

→ Repair as necessary.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

→ Go To 4

Turn the ignition on.
With the DRBIII

t, read and record the AAT Sensor Temperature value

Using the DRB Temperature Probe #CH7050, measure the ambient air temperature
near the AAT sensor.
Is the AAT Sensor value with -15°C (5°F) of the temperature probe reading?

All

Yes

→ Go To 5

→ Go To 7

DRIVEABILITY - NGC

P0128-THERMOSTAT RATIONALITY —

Continued

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