Test Procedure

WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2005 Mercury Sable, 2005 Mercury Mountaineer, 2005 Mercury Monterey, 2005 Mercury Montego, and 2005 Mercury Mariner. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Proceed to DTC testing steps listed in FAULT CODE SETTING CONDITION table of fault code setting condition.

FAULT CODE SETTING CONDITION

Fault Code	Application	Setting Condition	Testing
P1289, P1290	-	KOEO, KOER	DL7
P1289, P128A, P1290	-	Continuous Memory	DL14
P1299	-	KOEO, KOER, Continuous Memory	DL20
P0116	Vehicles with only a cylinder head temperature (CHT) sensor	Continuous Memory	DL23
P0116	Vehicles with only an engine coolant temperature (ECT) sensor or both CHT and ECT sensor	Continuous Memory	DX13
P0117, P0118	Vehicles with only a cylinder head temperature (CHT) sensor	KOEO, KOER	DL7
P0117, P0118, P0119	Vehicles with only a cylinder head temperature (CHT) sensor	Continuous Memory	DL14
P0117,	Vehicles with only an engine coolant temperature (ECT) sensor or both CHT and ECT sensor	KOEO, KOER	DX11
P0117, P0118, P0119	Vehicles with only an engine coolant temperature (ECT) sensor or both CHT and ECT sensor	Continuous Memory	DX15
P0118	Vehicles with only an engine coolant temperature (ECT) sensor or both CHT and ECT sensor	KOEO, KOER	DX7
P0125, P0128	Vehicles with only a cylinder head temperature (CHT) sensor	Continuous Memory	DL21
P0125, P0128	Vehicles with only an engine coolant temperature (ECT) sensor or both CHT and ECT sensor	Continuous Memory	DX18

DL1 SELF-TEST DTCS P1288 OR P1116: CHECK THE COOLING SYSTEM

WARNING: TO AVOID PERSONAL INJURY DO NOT UNSCREW THE COOLANT PRESSURE RELIEF CAP WHILE THE ENGINE IS OPERATING OR HOT. THE COOLING SYSTEM IS UNDER PRESSURE. STEAM AND HOT LIQUID CAN COME OUT FORCEFULLY WHEN THE CAP IS LOOSENED SLIGHTLY.

The DTC indicates the temperature sensor is out of self-test range. The engine is not at normal operating temperature.
Possible causes:
- Cold engine.
- Low engine coolant.
- Engine overheat.
- Damaged harness.
- CHT sensor.
- Damaged PCM.
Check the vehicle coolant level.

Is the cooling system OK?

Yes	No
GO to DL2.	REFER to ENGINE COOLING for cooling system diagnostics. REPAIR as necessary.

DL2 CHECK IF THE VEHICLE ENGINE STARTS

Attempt to start the engine.

Does the engine start and run normally?

Yes	No
GO to DL5.	GO to DL3.

DL3 CHECK THE RESISTANCE OF THE CHT SENSOR WITH THE ENGINE OFF

Key in OFF position.
CHT Sensor connector disconnected.

Measure the resistance between:

(+) CHT Sensor Connector, Component Side	(-) CHT Sensor Connector, Component Side
CHT	SIGRTN

NOTE: Refer to the CYLINDER HEAD TEMPERATURE SENSOR EXPECTED VALUES chart at the beginning of this test for resistance specifications.

Is the resistance within specification?

Yes	No
GO to DL4.	INSTALL a new CHT sensor.

DL4 CHECK CIRCUIT FROM MODULE TO COMPONENT

CHT Sensor connector connected.
Key in ON position.
Access the PCM and monitor the CHT V PID.
Using the data collected from the previous step, compare temperature resistance measured at the sensor to the PID temperature voltage measured at the PCM.

NOTE: Refer to the CYLINDER HEAD TEMPERATURE SENSOR EXPECTED VALUES chart at the beginning of this test for resistance specifications.

Does the measured value at the sensor agree with measured PID value at the PCM?

Yes	No
No start or stalls. Concern is elsewhere. RETURN to SYMPTOM CHARTS - GASOLINE MODELS for further direction.	CHECK the harness. GO to DL11.

DL5 CHECK THE CHT SENSOR OPERATION

Run the engine until the engine temperature stabilizes.
Verify the upper radiator hose is hot and the cooling system is pressurized.
Check for self-test DTCs:

Are DTCs P1116 or P1288 present?

Yes	No
GO to DL6.	The engine temperature was not stabilized. REPAIR any other DTCs as necessary.

DL6 CHECK THE RESISTANCE OF THE CHT SENSOR

Vehicle must be at normal operating temperature.
Key in OFF position.
CHT Sensor connector disconnected.

Measure the resistance between:

(+) CHT Sensor Connector, Component Side	(-) CHT Sensor Connector, Component Side
CHT	SIGRTN

NOTE: Refer to the CYLINDER HEAD TEMPERATURE SENSOR EXPECTED VALUES chart at the beginning of this test for resistance specifications.

Is the resistance within specification?

Yes	No
INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) .	INSTALL a new CHT sensor.

DL7 DTCS P0117, P0118, P1289 OR P1290: ACCESS THE CHT PID AND CHECK THE VOLTAGE

Key in ON position.
Access the PCM and monitor the CHT V PID.

Is the voltage less than 0.2 V?

Yes	No
Key in OFF position. GO to DL8.	Key in OFF position. GO to DL9.

DL8 CHECK FOR A GROUNDED CIRCUIT

CHT Sensor connector disconnected.
Key in ON position.
Access the PCM and monitor the CHT V PID.

Is the voltage greater than 4.6 V?

Yes	No
INSTALL a new CHT sensor.	GO to DL13.

DL9 CHECK THE CHT CIRCUIT FOR A SHORT TO POWER

CHT Sensor connector disconnected.
Key in ON position.

Measure the voltage between:

(+) CHT Sensor Connector, Harness Side	(-)
CHT	Ground

Is the voltage greater than 5.5 V?

Yes	No
Key in OFF position. REPAIR the short circuit to PWR. CHECK the CHT sensor for damage. GO to DL10.	Key in OFF position. GO to DL10.

DL10 CHECK THE RESISTANCE OF THE CHT SENSOR WITH THE ENGINE OFF

CHT Sensor connector disconnected.

Measure the resistance between:

(+) CHT Sensor Connector, Component Side	(-) CHT Sensor Connector, Component Side
CHT	SIGRTN

NOTE: Refer to the CYLINDER HEAD TEMPERATURE SENSOR EXPECTED VALUES chart at the beginning of this test for resistance specifications.

Is the resistance within specification?

Yes	No
GO to DL11.	INSTALL a new CHT sensor.

DL11 CHECK THE SIGNAL AND SIGRTN CIRCUITS FOR AN OPEN IN THE HARNESS

PCM connector disconnected.

Measure the resistance between:

(+) CHT Sensor Connector, Harness Side	(-) PCM Connector, Harness Side
CHT	CHT
SIGRTN	SIGRTN

Are the resistances less than 5 ohms?

Yes	No
GO to DL12.	REPAIR the open circuit.

DL12 CHECK THE SENSOR SIGNAL FOR A SHORT TO VREF

Key in OFF position.
PCM connector disconnected.

Measure the resistance between:

(+) PCM Connector, Harness Side	(-) PCM Connector, Harness Side
CHT	VREF

Is the resistance greater than 10K ohms?

Yes	No
INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) .	REPAIR the short circuit to VREF.

DL13 CHECK THE SENSOR SIGNAL FOR A SHORT TO GROUND

Key in OFF position.
PCM connector disconnected.

Measure the resistance between:

(+) PCM Connector, Harness Side	(-) PCM Connector, Harness Side
CHT	SIGRTN

Measure the resistance between:

(+) PCM Connector, Harness Side	(-) 12 Volt Vehicle Battery
CHT	Negative terminal

Is the resistance greater than 10K ohms?

Yes	No
INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) .	REPAIR the short circuit.

DL14 DTCS P0117, P0118, P0119, P1117, P1289, P1290 OR P128A: INTERMITTENT CHECK

Key in ON position.
Access the PCM and monitor the CHT V PID.
While observing the PID, carry out the following:
- Tap on the sensor to simulate road shock.
- Wiggle the sensor connector.

Is there a large change in the voltage reading?

Yes	No
DISCONNECT and INSPECT the connector. If OK, INSTALL a new CHT sensor.	GO to DL15.

DL15 CHECK THE ELECTRONIC ENGINE CONTROL (EC) WIRING HARNESS

Access the PCM and monitor the CHT V PID.
While observing the PID, carry out the following:
- Wiggle, shake, and bend small sections of the wiring harness while working from the sensor to the PCM.

Is there a large change in the voltage reading?

Yes	No
ISOLATE the fault. Repair as necessary.	GO to DL16.

DL16 CHECK THE PCM AND VEHICLE HARNESS CONNECTORS

PCM connector disconnected.
CHT Sensor connector disconnected.

Are the connectors and terminals OK?

Yes	No
The fault is not present at this time. DISREGARD the current diagnostic trouble code (DTC) at this time. ADDRESS the next DTC. GO to POWERTRAIN DTC CHARTS AND DESCRIPTIONS - GASOLINE MODELS .	REPAIR as necessary.

DL17 SELF-TEST DTC P1285: EARLY WARNING OF ENGINE OVERHEAT CONDITION

An engine overheat condition was sensed by the CHT sensor.
Check the cooling system for:
- Correct coolant level.
- Internal or external coolant leaks.
- Blockage of the radiator.
- Cooling fan operation.

NOTE: If the electric cooling fan does not operate, return to SYMPTOM CHARTS - GASOLINE MODELS for electric cooling fan DTC or symptom diagnosis.

Is the cooling system OK?

Yes	No
Check: CHT sensor GO to DL18.	REFER to the ENGINE COOLING for cooling system diagnostics. Repair as necessary.

DL18 CHECK THE OPERATION OF THE CYLINDER HEAD TEMPERATURE SENSOR

Run the engine until the engine temperature stabilizes.
Verify the upper radiator hose is hot and the cooling system is pressurized.
Check for self-test DTCs:

Is DTC P1285 present?

Yes	No
GO to DL19.	Engine overheat temperature was not detected. REPAIR any other DTCs as necessary.

DL19 CHECK THE RESISTANCE OF THE CHT SENSOR

Vehicle must be at normal operating temperature.
Key in OFF position.
CHT Sensor connector disconnected.

Measure the resistance between:

(+) CHT Sensor Connector, Component Side	(-) CHT Sensor Connector, Component Side
CHT	SIGRTN

Refer to the CYLINDER HEAD TEMPERATURE SENSOR EXPECTED VALUES chart at the beginning of this test for resistance specifications.

Is the resistance within specification?

Yes	No
INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) .	INSTALL a new CHT sensor.

DL20 SELF-TEST DTC P1299: INDICATES AN ENGINE OVERHEAT CONDITION

NOTE: Refer to POWERTRAIN DTC CHARTS AND DESCRIPTIONS - GASOLINE MODELS for possible causes and additional DTC description information.

Check the engine coolant level.

Is the engine coolant fill level correct?

Yes	No
REFER to the ENGINE COOLING to diagnose the overheating condition.	REFER to the ENGINE COOLING to diagnose the loss of coolant.

DL21 SELF-TEST DTCS P0125 OR P0128: CHECK THE ENGINE COOLANT LEVEL

Diagnostic Trouble Code (DTC) indicates the engine coolant temperature has not achieved the required engine operation temperature level, since start-up within a specified amount of time.
Possible causes:
- Insufficient warm up time.
- Leaking or stuck-open thermostat.
- Low engine coolant.
Check the engine coolant level.

Is the engine coolant fill level correct?

Yes	No
GO to DL22.	REFER to the ENGINE COOLING to diagnose the loss of coolant.

DL22 CHECK SENSOR OPERATION

Run the engine until the engine temperature stabilizes.
Verify the upper radiator hose is hot and the cooling system is pressurized.
Access the PCM and monitor the CHT PID.

Is the temperature greater than 77°C (170.6°F)?

Yes	No
Test complete.	REFER to the ENGINE COOLING for cooling system diagnostics.

DL23 DTC P0116: CHECK THE RESISTANCE OF THE CHT SENSOR WITH THE ENGINE OFF

NOTE: Verify the engine temperature is at ambient room temperature before continuing with this test. A soak period of 6 hours may be required. Refer to POWERTRAIN DTC CHARTS AND DESCRIPTIONS - GASOLINE MODELS , for information concerning P0116.

Key in OFF position.
CHT Sensor connector disconnected.

Measure the resistance between:

(+) CHT Sensor Connector, Component Side	(-) CHT Sensor Connector, Component Side
CHT	SIGRTN

Refer to the CYLINDER HEAD TEMPERATURE SENSOR EXPECTED VALUES chart at the beginning of this test for resistance specifications.

Is the resistance within specification?

Yes	No
CONNECT the CHT GO to DL24.	INSTALL a new CHT sensor.

DL24 DTC P0116: CHECK THE RESISTANCE OF THE CHT SENSOR

Run the engine until the engine temperature stabilizes.
Key in OFF position.
NOTE: Verify the engine is at operating temperature before taking the CHT reading.
CHT Sensor connector disconnected.

Measure the resistance between:

(+) CHT Sensor Connector, Component Side	(-) CHT Sensor Connector, Component Side
CHT	SIGRTN

Refer to the CYLINDER HEAD TEMPERATURE SENSOR EXPECTED VALUES chart at the beginning of this test for resistance specifications.

Is the resistance within specification?

Yes	No
The fault is not present at this time CARRY OUT the OBD drive cycle to determine if fuel, HO2S, catalyst and misfire monitors can be executed. REFER to ON BOARD DIAGNOSTIC (OBD) DRIVE CYCLE Retest if necessary.	INSTALL a new CHT sensor.

DL25 DTC P0298: ENGINE OIL OVER TEMPERATURE CONDITION

NOTE: Engine oil temperature protection strategy in the PCM has been activated. This protects the engine against mechanical damage due to overheating. Refer to POWERTRAIN DTC CHARTS AND DESCRIPTIONS - GASOLINE MODELS for possible causes and additional DTC description information.

Check for an overheating condition and base engine concerns.

Are there any overheating or base engine concerns?

Yes	No
ISOLATE the fault. REPAIR as necessary.	GO to DL26.

DL26 CHECK FOR CHT DTCS

Check for self-test DTCs:

Are DTCs P1285, P1288, P1289 or P1299 present?

Yes	No
DISREGARD the engine oil temperature (EOT) diagnostic trouble code (DTC) at this time. ADDRESS the next DTC. GO to POWERTRAIN DTC CHARTS AND DESCRIPTIONS - GASOLINE MODELS .	GO to DL27.

DL27 ROAD TEST THE VEHICLE AND MONITOR FOR ENGINE OVER TEMPERATURE

Access the Freeze Frame Data (if available) and record the DTC malfunction conditions.
Access the PCM and monitor the CHT V PID.
Test drive the vehicle and allow the engine to reach normal operating temperature.
Observe CHT PID.

Does the engine overheat?

Yes	No
REFER to the ENGINE COOLING for cooling system diagnostics. REPAIR as necessary.	Unable to duplicate or identify the fault at this time.

DL28 ENGINE TEMPERATURE WARNING INDICATOR LAMP ON OR TEMPERATURE GAUGE INDICATES HOT, BUT ENGINE IS NOT OVERHEATING

NOTE: PCM Self-Test must be carried out prior to entering this Pinpoint Test.

Was PCM Self-Test carried out prior to entering this Pinpoint Test?

Yes	No
No DTCs present GO to DL29.	Concern is elsewhere. RETURN to POWERTRAIN DTC CHARTS AND DESCRIPTIONS - GASOLINE MODELS for further direction.

DL29 ENGINE TEMPERATURE INDICATOR LAMP ON OR TEMPERATURE GAUGE INDICATES HOT, WITH NO DTCS

NOTE: The Engine Temperature Warning Indicator (gauge or lamp) is a warning system that gives the driver information during an engine overheating condition. The PCM monitors the CHT sensor and determines if fail-safe cooling mode is needed. If fail-safe cooling mode is needed, the PCM can signal the driver in 2 ways:

Temperature Warning Indicator information received through the vehicle Communication Link (SCP or CAN):
The PCM sends a SCP or CAN message to the instrument cluster to signal an overheating condition. This causes the instrument cluster indicator to illuminate and/or forces the temperature gauge to the H (hot) zone. DTC P1285 will also be stored in the PCM.
Temperature Warning Indicator hard wired to the PCM:
The PCM grounds the engine temperature warning circuit when the engine is overheating. This causes the instrument cluster indicator to illuminate and/or forces the temperature gauge to the H (hot) zone. DTC P1285 will also be stored in the PCM.
This pinpoint test ONLY diagnoses the PCM hardwire systems with no PCM DTCs. Currently only the 2.3L Ranger, Crown Victoria, and Grand Marquis use the hardwire system.
For any other type of Engine Temperature Warning Indicator system problems, refer to the INSTRUMENT CLUSTER .
Possible causes:
- Damaged engine coolant temperature sensor.
- Instrument cluster concern.
- Wiring harness fault between PCM and Instrument Cluster.
- Damaged PCM.
PCM connector disconnected.
Key in ON position.

Does the engine temperature warning indicator lamp turn OFF (prove out) and\or the temperature gauge return to the normal zone with the PCM disconnected?

Yes	No
Key in OFF position. INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) .	PCM has not attempted to set the Warning Indicators. REFER to the INSTRUMENT CLUSTER to diagnose the temperature gauge.