Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

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HOMESERVICE MANUALSMERCURY2010MARINER HYBRID, AWDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT VARIANT/TRIMSECTION 10 (AUTOMATIC TRANSMISSION - 6F35)DIAGNOSIS AND TESTINGPINPOINT TESTS - OSC EQUIPPED VEHICLEPINPOINT TESTSPINPOINT TEST B: TFT SENSOR

2010 Mercury Mariner Hybrid, AWD

Pinpoint Test B: TFT Sensor

2010 Mercury Mariner Hybrid, AWDSECTION Pinpoint Test B: TFT Sensor

WARNING: This page is about a different variant/trim than selected.

NOTE: Refer to the SOLENOID BODY LEADFRAME TRANSMISSION FLUID TEMPERATURE (TFT) SENSOR PIN illustration within the TRANSAXLE CONNECTOR LAYOUTS procedure.

B1 ELECTRONIC DIAGNOSTICS
- Check to make sure the transaxle vehicle harness C168a is fully seated, terminals are fully engaged in connector and in good condition before proceeding.
- Have the above items been checked?
1. Yes: GO to B2 .
2. No: CARRY OUT checks. ERASE the codes. REPEAT the self-test.
B2 CHECK THE TFT SENSOR CIRCUITS FOR AN OPEN
- Ignition OFF.
- Disconnect: Transaxle Vehicle Harness C168a.
- Disconnect: PCM Transaxle Harness C175T.
- Use a mirror to inspect both ends of the connector for damage or pushed-out pins, corrosion, loose wires and missing or damaged seals.
- Measure the resistance between PCM transaxle harness C175T-19, circuit VET27 (BN/YE) and transaxle vehicle harness C168a-2 circuit VET27 (BN/YE).
  
  Fig 1: Measuring Resistance Between PCM Transaxle Harness C175T-19, Circuit VET27 (BN/YE) And Transaxle Vehicle Harness C168A-2 Circuit VET27 (BN/YE)
  Courtesy of FORD MOTOR CO.
- Measure the resistance between PCM transaxle harness C175T-41, circuit RE406 (GY/VT) and transaxle vehicle harness C168a-1, circuit RE406 (GY/VT).
  
  Fig 2: Measuring Resistance Between PCM Transaxle Harness C175T-41, Circuit RE406 (GY/VT) And Transaxle Vehicle Harness C168A-1, Circuit RE406 (GY/VT)
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
1. Yes: GO to B3 .
2. No: REPAIR the circuit(s) for an open. CONNECT all components. TEST the system for normal operation.
B3 CHECK THE TFT SENSOR CIRCUITS FOR A SHORT TO GROUND
- Disconnect: Catalyst Monitor Sensor (CMS) C141.
- Disconnect: CMS C142.
- Measure the resistance between transaxle vehicle harness C168a-2, circuit VET27 (BN/YE) and ground.
  
  Fig 3: Measuring Resistance Between Transaxle Vehicle Harness C168A-2, Circuit VET27 (BN/YE) And Ground
  Courtesy of FORD MOTOR CO.
- Measure the resistance between transaxle vehicle harness C168a-1, circuit RE406 (GY/VT) and ground.
  
  Fig 4: Measuring Resistance Between Transaxle Vehicle Harness C168A-1, Circuit RE406 (GY/VT) And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 10, 000 ohms?
1. Yes: GO to B4 .
2. No: REPAIR the circuit(s) for a short to ground. CONNECT all components. TEST the system for normal operation.
B4 CHECK THE TFT CIRCUITS FOR A SHORT TO VPWR
- Measure the voltage between transaxle vehicle harness C168a-2, circuit VET27 (BN/YE) and ground.
  
  Fig 5: Measuring Voltage Between Transaxle Vehicle Harness C168A-2, Circuit VET27 (BN/YE) And Ground
  Courtesy of FORD MOTOR CO.
- Measure the voltage between transaxle vehicle harness C168a-1, circuit RE406 (GY/VT) and ground.
  
  Fig 6: Measuring Voltage Between Transaxle Vehicle Harness C168A-1, Circuit RE406 (GY/VT) And Ground
  Courtesy of FORD MOTOR CO.
- Is any voltage present?
1. Yes: REPAIR the circuit(s) for a short to voltage. CONNECT all components. TEST the system for normal operation.
2. No: GO to B5 .

B5 CHECK THE RESISTANCE OF THE TFT SENSORS/HARNESS

Vehicle must be at normal operating temperature.
Connect: Transaxle Vehicle Harness C168a.
TEST 1.
Measure and record the resistance between PCM transaxle harness C175T-19, circuit VET27 (BN/YE) and C175T-41, circuit RE406 (GY/VT).

Fig 7: Measuring Resistance Between PCM Transaxle Harness C175T-19, Circuit VET27 (BN/YE) And C175T-41, Circuit RE406 (GY/VT)
Courtesy of FORD MOTOR CO.

Compare the resistance value to the following table ranges:

TRANSMISSION FLUID TEMPERATURE (TFT)

°C	°F	Resistance (Ohms)
-40 to -20	-40 to -4	1076K-269K
-19 to -1	-3 to 31	309K-91K
0-20	32-68	104K-35K
21-40	69-104	40K-15K
41-70	105-158	17K-4.9K
71-90	159-194	5.6K-2.5K
91-110	195-230	3.0K-1.4K
111-130	231-266	1.7K-0.8K
131-150	267-302	0.97K-0.56K

TEST 2.
Check for intermittent short or open.
If the resistance was between 0.8K and 100K ohms carry out the following test. If the transaxle is warm, allow it to cool. Check the TFT sensor resistance again. Compare the resistance with the initial resistance. The resistance should decrease if the transaxle was heated and should increase if the transaxle was allowed to cool. If correct, then change in the resistance occurs, repeat On-Board Diagnostic (OBD).
Is the resistance in the range?

Yes: INSTALL a new PCM. CONNECT all components. TEST the system for normal operation.
No: INSTALL a new solenoid body leadframe. REFER to SOLENOID BODY LEADFRAME . RECONNECT all components. TEST the system for normal operation.

RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.