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Test DA: Temperature Sensor Test (IAT, ECT & EOT): Testing

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

Fault Code KOEO KOER Continuous Memory
P0112  DA20  DA20  DA90
P0113  DA10  DA10  DA90
P0116 (ECT Sensor) 1       DA80
P0117 (ECT Sensor) 1   DA20  DA20  DA90
P0118 (ECT Sensor) 1   DA10  DA10  DA90
P0125 (ECT Sensor) 1       DA100
P0128 (ECT Sensor) 1       DA100
P0196  DA110  DA110  DA110
P0197  DA111  DA111  DA111
P0198  DA111  DA111  DA111
P0217 (ECT Sensor) 1   DA105  DA105  DA105
P0298      DA130
P1112      DA90
P1116 (ECT Sensor) 1   DA1  DA1  
P1117 (ECT Sensor) 1       DA90
P1184  DA110  DA110  DA110
(1)
For engines with a Cylinder Head Temperature Sensor see FAULT CODE SETTING CONDITION .
    NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  1. 1) For KOEO & KOER Only DTC P1116: Check Operation Of ECT Sensor
    This DTC indicates sensor is out of self-test range. Correct range for measurement is .3-3.7 volts. Check for following possible causes:
    • Overheating Condition
    • Malfunctioning Thermostat
    • Faulty ECT Sensor
    • Low Coolant Level
    • Faulty Harness Or Connector
    • Faulty PCM

    If directed here because engine is a no-start, go to step  3). If vehicle has a stalling concern, go to appropriate symptom under SYMPTOMS in TROUBLE SHOOTING - NO CODES - CNG, FLEX-FUEL & GASOLINE article. Start and run engine at 2000 RPM until engine reaches normal operating temperature. Ensure upper radiator hose is hot and pressurized. Repeat KOER ON-DEMAND SELF-TEST . If DTC P1116 is present, go to next step. If DTC P1116 is not present, engine was not at closed loop operating conditions when KOER ON-DEMAND SELF-TEST was performed. Repair any other DTCs that are present.

  2. 2) Check VREF Circuit Voltage To TP Sensor

    Turn ignition switch to OFF position. Disconnect Throttle Position (TP) sensor. Turn ignition switch to ON position. Using a DVOM, measure voltage between VREF and SIG RTN terminals at TP sensor harness connector. See Figure-Figure . If voltage is 4-6 volts, reconnect TP sensor and go to next step. If voltage is not 4-6 volts, go to TEST C, step  1).

  3. 3) Check ECT Sensor Resistance With Engine Off

    Turn ignition switch to OFF position. Disconnect ECT sensor. Using a DVOM, measure resistance between ECT sensor SIG and SIG RTN circuit terminals. See Fig 1. Compare sensor resistance to appropriate temperature specification in illustration. See Fig 7. If resistance is not as specified, replace faulty ECT sensor. If resistance is as specified, perform following step as applicable:
    • For diagnosing vehicles with an ECT sensor related fault, or engine is a no-start, DO NOT service DTC P1116 at this time. See NO START/NORMAL CRANK symptom under SYMPTOMS in TROUBLE SHOOTING - NO CODES - CNG, FLEX-FUEL & GASOLINE article.
    • For diagnosing vehicles with cooling fan concerns or engine cooling concerns, DO NOT service DTC P1116 at this time. Service next DTC. If no other DTCs are present, repair by symptom. See SYMPTOMS in TROUBLE SHOOTING - NO CODES - CNG, FLEX-FUEL & GASOLINE article.
    • For vehicles with no other fault conditions or DTCs, go to next step.
    Fig 1: Identifying Engine Coolant Temperature Sensor Circuits & Connector Terminals
    G00152722Courtesy of FORD MOTOR CO.
    Fig 2: Identifying Engine Oil Temperature Sensor Circuits & Connector Terminals (LS & Thunderbird)
    G00152723Courtesy of FORD MOTOR CO.
    Fig 3: Identifying MAF With Integrated Intake Air Temperature Sensor Circuits & Connector Terminals (Focus 2.3L)
    G00152724Courtesy of FORD MOTOR CO.
    Fig 4: Identifying MAF With Integrated Intake Air Temperature Sensor Circuits & Connector Terminals (LS & Thunderbird)
    G00152725Courtesy of FORD MOTOR CO.
    Fig 5: Identifying MAF With Integrated Intake Air Temperature Sensor Circuits & Connector Terminals (All Others)
    G00152726Courtesy of FORD MOTOR CO.
    Fig 6: Identifying Intake Air Temperature Sensor Circuits & Connector Terminals
    G00152727Courtesy of FORD MOTOR CO.
    4. NOTE: Engine must be at normal operating temperature before taking temperature sensor measurements.
    Fig 7: IAT, ECT & EOT Sensor Specifications
    G00077804Courtesy of FORD MOTOR CO.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 4) to step 10). No test procedures have been omitted.

  4. 4) Check ECT Sensor Resistance With Engine Running
    Reconnect all connectors. Start engine and operate at 2000 RPM for 2 minutes. Turn ignition switch to OFF position. Disconnect ECT sensor. Using a DVOM, measure resistance between ECT sensor SIG and SIG RTN circuit terminals. See Fig 1. Compare sensor resistance to appropriate temperature specification in illustration. See Fig 7. If resistance is not as specified for, replace faulty ECT sensor. If resistance is as specified, replace PCM.
    5. NOTE: For LS and Thunderbird with electronic throttle control, go to next step. For additional testing information, see DIAGNOSTIC AIDS .

  5. 10) For KOEO & KOER Only DTC P0113 Or P0118: Check Voltage Between VREF & SIG RTN
    DTC P0113 (IAT) or P0118 (ECT) indicates IAT or ECT sensor signal is more than self-test maximum. Maximum measurement should be 4.6 volts at -58°F (-50°C). Check for following possible causes:
    • Open Circuit In Harness Or Connector
    • Sensor Signal Short To Power
    • Faulty Sensor
    • Faulty PCM

    Turn ignition switch to OFF position. Disconnect TP sensor connector. Turn ignition switch to ON position. Using a DVOM, measure voltage between VREF and SIG RTN circuits at TP harness connector. See Figure-Figure . If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, go to TEST C, step  1).

  6. 11) Simulate Opposite Signal To PCM

    Turn ignition switch to OFF position. Disconnect suspect temperature sensor. Connect a jumper wire between suspect sensor harness connector SIG and SIG RTN circuit terminals. With scan tool installed, turn ignition switch to ON position.
    NOTE: If a scan tool communication concern exists, remove jumper wire and go to step  13).

    Using scan tool, access suspect sensor ECT-V or IAT-V PID from PID/DATA MONITOR & RECORD menu. If PID value is less than .2 volt or more than 248°F (120°C), replace suspect sensor. If PID value is .2 volt or more, or 248°F (120°C) or less, remove jumper wire and go to next step.

  7. 12) Check Temperature Sensor SIG & SIG RTN Circuits For Open In Harness

    Turn ignition switch to OFF position. Ensure suspect temperature sensor is disconnected. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance of SIG RTN circuit between PCM harness connector and suspect sensor harness connector. Record resistance. Using a DVOM, measure resistance of SIG circuit between PCM harness connector and suspect sensor harness connector. See Fig 1-Fig 6 . See WIRING DIAGRAMS . If both resistance measurements are less than 5 ohms, replace PCM. If either resistance measurement is 5 ohms or more, repair open in affected circuit.

  8. 13) Check Temperature Sensor SIG Circuit For Short To VREF In Harness

    Turn ignition switch to OFF position. Disconnect PCM connector(s). Using a DVOM, measure resistance between suspect sensor VREF circuit and SIG circuit (ECT or IAT) terminals at PCM harness connector. See Fig 1-Fig 6 . See WIRING DIAGRAMS . If resistance is more than 10 k/ohms, replace PCM. If resistance is 10 k/ohms or less, repair short to VREF in wiring harness.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 13) to step 20). No test procedures have been omitted.
    9. NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  9. 20) For KOEO & KOER Only DTC P0112 Or P0117: Simulate Opposite Signal To PCM
    DTC P0112 (IAT) or P0117 (ECT) indicates sensor signal is less than self-test minimum. Minimum signal for IAT and ECT sensor is .2 volt or 250°F (121°C). Possible causes for these faults are:
    • Circuit Grounded In Wiring Harness
    • Faulty Sensor
    • Faulty Connection
    • Faulty PCM

    Turn ignition switch to OFF position. Disconnect suspect temperature sensor connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. Using scan tool, access ECT-V or IAT-V PID from PID/DATA MONITOR & RECORD menu. For LS and Thunderbird with electronic throttle control, if PID value is 4.2 volts or less, or -40°F (-40°C) or more, go to step  22). All others, go to next step. If PID value is more than 4.2 volts, or less than -40°F (-40°C), replace faulty temperature sensor.

  10. 21) Check VREF Voltage To TP Sensor

    Turn ignition switch to OFF position. Disconnect TP sensor connector. Turn ignition switch to ON position. Using a DVOM, measure voltage between VREF and SIG RTN terminals at TP sensor harness connector. If voltage is 4-6 volts, VREF voltage is okay. Reconnect TP sensor and go to next step. If voltage is not 4-6 volts, see TEST C, step  1).

  11. 22) Check Temperature Sensor SIG Circuit For Short To Ground

    Turn ignition switch to OFF position. Ensure suspect sensor is disconnected. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance between suspect sensor SIG, SIG RTN and PWR GND circuits at PCM harness connector. See PCM PWR GND, SIG RTN & VREF TERMINAL IDENTIFICATION  table. See Fig 1-Fig 6 . See WIRING DIAGRAMS . If any resistance measurement is 10 k/ohms or less, repair short to ground in affected circuit. If all resistance measurements are more than 10 k/ohms, replace PCM.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 22) to step 80). No test procedures have been omitted.
    12. NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  12. 80) For Continuous Memory Only DTC P0116: Check Temperature Sensor Resistance With Engine Off
    DTC P0116 indicates ECT sensor drifted higher than normal sensor calibration curve and could prevent one or more OBD-II monitors from functioning. PCM will set DTC P0116 when all of the following conditions are met:
    • Engine coolant temperature at engine start up exceeds IAT temperature by more than calibrated value, about 30°F (-1°C).
    • Engine coolant temperature exceeds a calibrated value, about 225°F (107°C).
    • Fuel, HO2S, catalyst and misfire monitors have not completed.
    • Calibrated timer to set DTC P0116 has expired.

    Possible causes for this fault are:

    • Faulty CHT Or ECT Sensor
    • Coolant System Fault

    Ensure engine temperature is at ambient room temperature before performing this test step. A soak period of 6 hours may be required. Soak period allows IAT and CHT or ECT to stabilize and not differ by more than a calibrated value. Turn ignition switch to OFF position. Disconnect ECT sensor. Using a DVOM, measure resistance between SIG and SIG RTN circuit terminals at suspect sensor harness connector. See Fig 1. Compare sensor resistance to appropriate temperature specification in illustration. See Fig 7. If resistance is not as specified, replace faulty sensor. If resistance is as specified, go to next step.

    13. NOTE: Engine must be at normal operating temperature before taking temperature sensor measurements.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 81) to step 90). No test procedures have been omitted.

  13. 81) DTC P0116: Check Temperature Sensor Resistance With Engine Running
    Reconnect suspect sensor connector. Start engine and operate at 2000 RPM for 2 minutes. Turn ignition switch to OFF position. Disconnect suspect sensor. Using a DVOM, measure resistance between SIG and SIG RTN circuits at suspect sensor terminals. See Fig 1. Compare sensor resistance to appropriate temperature specification in illustration. See Fig 7. If resistance is not as specified, verify thermostat and cooling system for correct operation. If okay, replace faulty sensor. If resistance is as specified, fault is not present at this time. Perform DRIVE CYCLES to determine if fuel, HO2S, catalyst and misfire monitors can be executed. Repeat QUICK TEST .
    14. NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  14. 90) For Continuous Memory Only DTCs P0112, P0113, P0118, P1112 & P1117: Check For Intermittent
    These DTCs indicate possible intermittent fault. Possible causes for these faults are:
    • Faulty Sensor
    • Faulty Sensor Connector
    • Open Or Grounded Circuit In Harness
    • Faulty PCM

    Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. Using scan tool, access ECT-V and IAT-V PID from PID/DATA MONITOR & RECORD menu. While observing appropriate PID, tap on sensor and wiggle sensor connector to simulate road shock. If no change in PID voltage reading occurs, go to next step. If any change in PID voltage reading occurs, turn ignition switch to OFF position. Inspect connectors for loose, damaged or corroded terminals. Repair as necessary. If connectors are okay, replace faulty temperature sensor. If directed here for Continuous Memory DTCs P1112 and P1117, perform DRIVE CYCLES to verify repair. Repeat QUICK TEST .

  15. 91) Check EEC-V Wiring Harness

    While still observing PID, wiggle and bend small sections of wiring harness working from sensor and going toward PCM. If no changes in PID voltage reading occurs, go to next step. If changes in PID voltage reading occurs, isolate fault and repair as necessary. If directed here for Continuous Memory DTCs P1112 and P1117, perform DRIVE CYCLES to verify repair. Repeat QUICK TEST .

  16. 92) Inspect PCM & Wiring Harness Connectors

    Turn ignition switch to OFF position. Disconnect suspect sensor and PCM connector(s). Inspect connector(s) for damaged terminals, corrosion and loose terminals. If connectors and terminals are damaged, repair as necessary. If directed here for Continuous Memory DTCs P1112 and P1117, perform DRIVE CYCLES to verify repair. Repeat QUICK TEST . If connectors and terminals are okay, fault cannot be identified at this time. Testing is complete. If directed here for Continuous Memory DTCs P1112 and P1117, perform DRIVE CYCLES to verify repair. Repeat QUICK TEST .
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 92) to step 100). No test procedures have been omitted.
    17. NOTE: For additional testing information, see DIAGNOSTIC AIDS .
    WARNING: To avoid personal injury, DO NOT loosen coolant pressure relief cap while engine is operating or hot. Cooling system is under pressure and steam and/or hot coolant can come out forcefully when cap is loosened slightly.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 100) to step 105). No test procedures have been omitted.

  17. 100) For Continuous Memory Only DTCs P0125 & P0128: Check Engine Coolant Level
    This DTC indicates CHT or ECT sensor has not reached the required temperature level to enter closed loop operating conditions within a specified amount of time after starting engine. Possible causes for this fault are:
    • Insufficient Engine Warm-Up Time
    • Thermostat Leaking Or Stuck Open
    • Malfunctioning CHT Or ECT Sensor
    • Low Coolant Level

    Check coolant level. If coolant level is correct, see appropriate COOLING FANS article in ENGINE COOLING. Repair cooling system as necessary. If coolant level is incorrect, add coolant to proper level, clear DTCs and repeat QUICK TEST .

    18. NOTE: For additional testing information, see DIAGNOSTIC AIDS .
    WARNING: To avoid personal injury, DO NOT loosen coolant pressure relief cap while engine is operating or hot. Cooling system is under pressure and steam and/or hot coolant can come out forcefully when cap is loosened slightly.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 105) to step 110). No test procedures have been omitted.

  18. 105) For KOEO, KOER & Continuous Memory DTC P0217: Engine Coolant Over Temperature
    This DTC indicates an engine overheat condition was detected by the engine temperature sensor (CHT or ECT depending how vehicle is equip). This condition will cause the boost from the supercharger to be bypassed to avoid potential engine damage. Possible causes are:
    • Engine cooling system concerns.
    • Low engine coolant level.
    • Base engine concerns.

    Check for blockage of radiator (air or coolant flow), water pump or hose problems and internal or external coolant leaks.

    Check coolant level. If coolant level is correct, see appropriate COOLING FANS article in ENGINE COOLING. Repair cooling system as necessary. If coolant level is incorrect, repair cooling system as necessary. Fill engine coolant to proper level. Complete DRIVE CYCLES to verify repair.

    19. NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  19. 110) For KOEO, KOER & Continuous Memory DTCs P0196 & P1184: Check Operation Of EOT Sensor
    This DTC indicates Engine Oil Temperature (EOT) sensor signal was out of self-test range. Correct range for measurement is .3-1.2 volt. Possible causes for this fault are:
    • Faulty Sensor Or Connector
    • Fault In Harness
    • Faulty PCM

    Connect scan tool to DLC. Start and operate engine at 2000 RPM until engine temperature becomes stabilized. Perform KOER ON-DEMAND SELF-TEST . If DTC P0196 or P1184 is present, turn ignition switch to OFF position and go to next step. If DTC P0196 or P1184 is not present, engine oil temperature was not at operating temperature. Repair other DTCs as necessary.

    20. NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  20. 111) For KOEO, KOER & Continuous Memory DTCs P0197 & P0198: Check Temperature Sensor Signal
    These DTCs indicate that the sensed EOT value from the EOT sensor is not within the PCM predicted engine oil temperature range, based on other PCM inputs, or engine oil temperature protection strategy in PCM has been activated by engine oil over-temperature condition. Possible causes for this fault are:
    • Engine not at operating temperature.
    • Cooling system problem of stuck thermostat.
    • EOT circuit failure.
    • Damaged PCM.
    • Damaged harness.
    • Damaged sensor.
    • Damaged harness connector.
    • Damaged PCM.
    • Very High Engine RPM For An Extended Period Of Time
    • Overheating Condition
    • Fault In EOT Sensor Or Harness
    • Base Engine Concerns

    Ensure scan tool is connected to DLC. Turn ignition switch to ON position. Using scan tool, access EOT-V PID from PID/DATA MONITOR & RECORD menu. If EOT-V PID voltage is less than .3 volt, go to next step. If EOT-V PID voltage is .3 volt or more go to step  115).

  21. 112) Simulate Opposite EOT Signal To PCM

    While monitoring EOT-V PID voltage, disconnect EOT sensor. If EOT-V PID voltage is now more than 4.2 volts, replace EOT sensor. If EOT-V PID voltage is still 4.2 volts or less, go to next step.

  22. 113) Check EOT SIG Circuit For Short To Ground

    Turn ignition switch to OFF position. Disconnect PCM connector(s). Using a DVOM, measure resistance between EOT and SIG RTN circuits and then between EOT and PWR GND circuits at the PCM harness connector. See Fig 8 or Fig 9 , and Fig 2 . See WIRING DIAGRAMS . If all resistance measurements are more than 10 k/ohms, replace PCM. If any resistance measurement is 10 k/ohms or less, repair short to ground in affected circuit.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 113) to step 115). No test procedures have been omitted.
    23. Fig 8: Identifying PCM Connector C175C Terminals (LS)
    G00152682Courtesy of FORD MOTOR CO.
    Fig 9: Identifying PCM Connector C175E Terminals (Thunderbird)
    G00152700Courtesy of FORD MOTOR CO.

  23. 115) Check For High EOT Signal

    If EOT-V PID voltage is more than 4.2 volts, go to next step. If EOT-V PID voltage is 4.2 volts or less, go to step  120).

  24. 116) Simulate Low Signal To PCM

    Disconnect EOT sensor. Connect jumper wire between EOT and SIG RTN circuits at EOT sensor harness connector. Turn ignition switch to ON position. Using scan tool, access EOT-V PID from PID/DATA MONITOR & RECORD menu. If EOT-V PID voltage is less than .3 volt, replace EOT sensor. If EOT-V PID voltage is .3 volt or more, go to next step.

  25. 117) Check EOT Sensor SIG & SIG RTN Circuits For Open In Harness

    Turn ignition switch to OFF position. Disconnect PCM connector(s). Using a DVOM, measure resistance of EOT circuit and SIG RTN circuit between PCM harness connector and EOT sensor. See Fig 2. If each resistance measurement is less than 5 ohms, replace PCM. If either resistance measurement is 5 ohms or more, repair open in affected circuit.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 117) to step 120). No test procedures have been omitted.

  26. 120) Intermittent EOT Sensor Check

    While observing EOT-V PID, tap on EOT sensor and wiggle sensor connector to simulate road shock. If no large change in EOT-V PID voltage reading occurs, go to next step. If any large change in EOT-V PID voltage reading occurs, turn ignition switch to OFF position. Inspect connectors for loose, damaged or corroded terminals. Repair as necessary. If connectors are okay, replace EOT sensor.

  27. 121) Check EOT EEC-V Wiring Harness

    While still observing EOT-V PID, wiggle and bend small sections of wiring harness working from sensor toward PCM. If no large change in EOT-V PID voltage reading occurs, fault is not present at this time. Perform DRIVE CYCLES to verify repair. Repeat QUICK TEST . If any large change in EOT-V PID voltage reading occurs, isolate fault and repair as necessary. Clear DTCs and perform DRIVE CYCLES to verify repair. Repeat QUICK TEST .

  28. 122) Check Temperature Sensor Resistance With Engine Running

    Run engine for two minutes at 1,500 RPM. Verify that engine is at correct operating temperature before taking reading. Using DVOM, measure temperature sensor resistance. Compare sensor resistance to appropriate temperature specification in illustration. See Fig 7. If resistance is within specification for the given engine temperature, fault is not present at this time, go to TEST Z step 1) . If resistance is not within specification, replace suspect sensor.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 122) to step 130). No test procedures have been omitted.
    29. NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  29. 130) For Continuous Memory Only DTC P0298: Engine Oil Over-Temperature Condition
    DTC P0298 indicates the Engine Oil Temperature Protection strategy in the PCM has been activated. This will temporarily prohibit high engine speed operation by disabling injectors, therefore reducing the risk of engine damage from high engine oil temperature. On engines which are equipped with an oil temperature sensor, the PCM reads oil temperature to determine if it is excessive. When an oil temperature sensor is not present, the PCM uses an oil algorithm to infer actual temperature. Engine shutdown strategy function is the same on vehicles with and without oil temperature sensors. Possible causes for this fault are:
    • Very high engine RPM for extended period of time.
    • Over-heating condition.
    • Malfunction EOT sensor or circuit (vehicles w/EOT sensor).
    • Base engine concerns.

    Engine oil temperature protection strategy in PCM has been activated. Check for engine overheating condition or engine mechanical concern. If concern is found, repair as necessary. If no concern is found, go to next step.

  30. 131) Check For EOT Sensor

    Engine oil temperature strategy can be activated in PCM with or without an EOT sensor. Ensure vehicle is equipped with an EOT sensor. If vehicle is equipped with an EOT sensor, go to step  111). If vehicle is not equipped with an EOT sensor, advise customer that an improper transmission gear selection, or excessive engine RPM for an extended period of time may have activated engine protection strategy in PCM.
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