Pinpoint Test B : TFT (Transmission Fluid Temperature) Sensor
Pinpoint Tests - OSC Equipped Vehicle
Pinpoint Tests
NOTE: Refer to all TSBs and On-Line Automotive Service Information System (OASIS) messages that pertain to the transmission concern and follow the procedure as described.
PINPOINT TEST B : TFT (Transmission Fluid Temperature) SENSOR
NOTE: Refer to the Transmission Vehicle Harness Connector illustration within the Transmission Connector Layouts Transmission Connector Layouts procedure.
NOTE: Refer to the Transmission Internal Harness Connector illustration within the Transmission Connector Layouts Transmission Connector Layouts procedure.
NOTE: Read and record all DTCs.
NOTE: Use the PID Chart for available diagnostic PIDs. Refer to Diagnostic Parameters Identification (PID) Chart Diagnostic Parameters Identification (PID) Chart.
NOTE: PCM connector C175T is used for 5.4L engine vehicles and connector C1551T is used for 6.8L engine vehicles.
B1 ELECTRONIC DIAGNOSTICS
- Select PARK.
- Ignition OFF.
- Check the transmission vehicle harness C1385 is fully seated, terminals are fully engaged in the connector and are in good condition before proceeding.
- Connect the scan tool.
- Ignition ON.
- Monitor the Transmission Fluid Temperature (TFT) sensor PID.
Can the TFT (Transmission Fluid Temperature) PID be monitored?
Yes
GO to B2.
No
If the scan tool did not enter PID list, REFER to Computers and Control Systems Information for diagnosis of the PCM.
B2 WARM-UP/COOL-DOWN CYCLE
- While monitoring the TFT (Transmission Fluid Temperature) PID, carry out the following test: If transmission is cold, operate to warm it up. If transmission is warm, allow transmission to cool down.
Does the TFT (Transmission Fluid Temperature) PID temperature increase as the transmission is warmed up or decrease as the transmission is cooled or does the TFT (Transmission Fluid Temperature) drop in and out of range?
Yes
CLEAR the DTCs. CARRY OUT the road test to verify if concern is still present. If concern is still present, REFER to Diagnosis By Symptom Diagnosis By Symptom to diagnose transmission overheating.
No
GO to B3.
B3 ELECTRICAL SIGNAL CHECK
- Disconnect: Transmission Vehicle Harness C1385.
- Visually inspect all wires and connector for damage.
- Measure the voltage between the transmission vehicle harness C1385-18, harness side and ground.
Is the voltage between 4.5 and 5.1 volts?
Yes
GO to B4.
No
REPAIR an open or short in the transmission vehicle harness. CLEAR the DTCs. TEST the system for normal operation. If normal operation does not return, INSTALL a new PCM.
B4 CHECK THE RESISTANCE OF THE TRANSMISSION FLUID TEMPERATURE SENSOR
- Measure the resistance between the transmission internal harness C1385-18 and C1385-22, component side.
- Record the resistance.
- Resistance should be approximately within the following ranges using the following chart.
Transmission Fluid Temperature
° C° F Resistance (Ohms) -40 to -20 -40 to -4 967K-284K -19 to -1 -3 to 31 284K-100K 0-20 32-68 100K-37K 21-40 69-104 37K-16K 41-70 105-158 16K-5K 71-90 159-194 5K-2.7K 91-110 195-230 2.7K-1.5K 111-130 231-266 1.5K-0.8K 131-150 267-302 0.8K-0.54K
Is the resistance within range?
Yes
REFER to Diagnosis By Symptom Diagnosis By Symptom 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: Transmission Fluid Temperature Sensor.
- Measure the resistance between the transmission internal harness and C1385-22 and the transmission fluid temperature sensor connector using the following chart.
Transmission Connector Terminal C1385-18 1 C1385-22 2
Is the resistances less than 5 ohms?
Yes
GO to B6.
No
INSTALL a new internal harness. CLEAR the DTCs. TEST the system for normal operation.
B6 CHECK THE INTERNAL HARNESS FOR A SHORT TO GROUND
- Measure the resistance between transmission internal harness C1385 and ground using the following chart.
Transmission Connector Ground C1385-18 Ground C1385-22 Ground
Is the resistance greater than 10,000 ohms?
Yes
GO to B7.
No
INSTALL a new internal harness. CLEAR the DTCs. TEST the system for normal operation.
B7 CHECK THE RESISTANCE OF THE TRANSMISSION FLUID TEMPERATURE SENSOR
- Measure the resistance between terminals 1 and 2 at the transmission fluid temperature sensor.
Transmission Fluid Temperature
° C° F Resistance (Ohms) -40 to -20 -40 to -4 967K-284K -19 to -1 -3 to 31 284K-100K 0-20 32-68 100K-37K 21-40 69-104 37K-16K 41-70 105-158 16K-5K 71-90 159-194 5K-2.7K 91-110 195-230 2.7K-1.5K 111-130 231-266 1.5K-0.8K 131-150 267-302 0.8K-0.54K
Is the resistance within specification?
Yes
CLEAR the DTCs. If the DTCs return and an overtemp condition is present, REFER to Computers and Control Systems Information. If the condition returns, INSTALL a new PCM.
No
INSTALL a new transmission fluid temperature sensor. CLEAR the DTCs. TEST the system for normal operation.