Pinpoint Test B: Transmission Fluid Temperature (TFT) Sensor
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- B1 ELECTRONIC DIAGNOSTICS
- Key in OFF position.
- Select PARK.
- Check to make sure the transmission harness connector is fully seated, terminals are fully engaged in connector and in good condition before proceeding.
- Connect the scan tool.
- Key in ON position.
- Enter the following diagnostic mode on the scan tool: Monitor PIDs For TFT.
- Does the vehicle enter PID/Data Monitor and Record?
Yes : REMAIN in PID/Data Control. GO to B2.
No : REPEAT procedure to enter PID. If vehicle did not enter PID, REFER to the INTRODUCTION - GASOLINE for diagnosis of powertrain control module (PCM) and NGS.
- B2 WARM-UP/COOL-DOWN CYCLE
- While monitoring the TFT PIDs, carry out the following test: If transmission is cold, operate to warm it up. If transmission is warm, allow transmission to cool down.
- Do the TFT PIDs increase as the transmission is warmed up or decrease as the transmission is cooled or does the TFT drop in and out of range?
Yes : If the TFT PIDs increase as the transmission is warmed or decrease as the transmission is cooled, CLEAR all DTCs. CARRY OUT the road test to verify if concern is still present. If concern is still present, REFER to DIAGNOSIS BY SYMPTOM in this section to diagnose transmission overheating.
No : GO to B3.
- B3 ELECTRICAL SIGNAL CHECK
- Disconnect: Transmission Harness Connector.
- Visually inspect all wires and connectors for damage.
- Measure the voltage between pin 18 harness side and ground.
- Is the voltage between 4.5 and 5.5 volts?
Yes : GO to B4.
No : REPAIR an open or short in the harness. TEST the system for normal operation. If normal operation does not return, INSTALL a new PCM.
- B4 CHECK THE RESISTANCE OF THE TFT SENSOR
- Measure the resistance between pins 18 and 22 at the transmission bulkhead body connector.
- Record the resistance.
- Resistance should be approximately in the following ranges:TRANSMISSION FLUID TEMPERATURE
°C °F Resistance (Ohms) -40 to -20 -40 to -4 967K - 284K -19 to -1 -3 to 31 284K - 100K 0 to 20 32 to 68 100K - 37K 21 to 40 69 to 104 37K - 16K 41 to 70 105 to 158 16K - 5K 71 to 90 159 to 194 5K - 2.7K 91 to 110 195 to 230 2.7K- 1.5K 111 to 130 231 to 266 1.5K - 0.8K 131 to 150 267 to 302 0.8K - 0.54K - Is the resistance in range?
Yes : REFER to DIAGNOSIS BY SYMPTOM in this section to diagnose an overheating concern.
No : GO to B5.
- B5 CHECK THE INTERNAL HARNESS FOR AN OPEN
- Drain the transmission fluid.
- Remove the transmission fluid pan.
- Disconnect: TFT Sensor Connector.
- Measure the resistance between TFT sensor connector pin 1 and the transmission bulkhead connector pin 18.
- Measure the resistance between TFT sensor connector pin 2 and the transmission bulkhead connector pin 22.
- Are the resistances less than 0.5 ohms?
Yes : GO to B6.
No : INSTALL a new internal harness. GO to B7.
- B6 CHECK THE INTERNAL HARNESS FOR A SHORT TO GROUND
- Measure the resistance between TFT sensor connector pins 18 and 22, and ground.
- Is the resistance greater than 10,000 ohms?
Yes : INSTALL a new internal harness.
No : GO to B7.
- B7 CHECK THE RESISTANCE AT THE SENSOR
- Measure the resistance between pins 1 and 2 at the TFT sensor.TRANSMISSION FLUID TEMPERATURE
°C °F Resistance (Ohms) -40 to -20 -40 to -4 967K - 284K -19 to -1 -3 to 31 284K - 100K 0 to 20 32 to 68 100K - 37K 21 to 40 69 to 104 37K - 16K 41 to 70 105 to 158 16K - 5K 71 to 90 159 to 194 5K - 2.7K 91 to 110 195 to 230 2.7K- 1.5K 111 to 130 231 to 266 1.5K - 0.8K 131 to 150 267 to 302 0.8K - 0.54K - Is the resistance within specification?
Yes : GO to B8.
No : INSTALL a new TFT sensor. CLEAR the DTCs. TEST the system for normal operation.
- Measure the resistance between pins 1 and 2 at the TFT sensor.
- B8 CHECK THE SENSOR FOR A SHORT TO GROUND
- Measure the resistance between pins 1 and 2 at the TFT sensor connector and ground.
- Is the resistance less than 10,000 ohms?
Yes : INSTALL a new TFT sensor.
No : INSTALL a new PCM. CLEAR the DTCs. If the DTCs return, an overtemp condition may exist. REFER to DIAGNOSIS BY SYMPTOM .