What does the 4R70W temp sensor do?

edspringer

Registered User
:confused: I have been trying to find out what the temp sensor located on the transmission's valve body does and what happens if it fails. Anyone know or had to replace it? Any info would be appreciated.

Ed Springer

90 Black XR7 5-speed: 142,740 miles, 70mm TB, Fresh Air Intake, '94 Supercharger Upgrade, 36# injectors, 190 l/h fuel pump, 5% SC Pulley, Raised SC Top, I/C Fan, Under drive Pulleys, Headers, Magnaflow Muffler (no cats) with stock resonators, 3:27 Gears, Rear Spring Air Bags, Ripper Shifter, 73 C&L MAF, Magnacore Wires, NGK Iridium Plugs, Royal Purple Synthetic Lubricants.

94 Red SC Auto: 93,660 miles, 70mm TB, Fresh Air Intake, Stock 90 SC Pulley, 38# injectors, 190 l/h fuel pump, Raised SC Top, I/C Fan, Under drive Pulleys, Headers, Raven Muffler (no cats) with stock resonators, 3:73 Gears, 73 C&L MAF, Magnacore Wires, NGK Iridium Plugs, TRANSGO Shift Kit, Haydon Auxiliary Transmission Cooler, ProTorque 2500 TC, Tokico Struts & Shocks, Royal Purple Synthetic Lubricants, American Racing 17” Sniper Wheels, Michelin Pilot Sport A/S, dynode 235 RWHP at 315 LBS. FT. Torque.
 
The temp sensor sends temp info back to the EEC for transmission control adjustments. As the trans fluid temp increases changes in line pressure and other operations adjust. Your Ford Emission Diag book explains in more detail what all is controlled.
 
Sounds Logical!!

Rich.......the reason I ask is when my tranny is cold the O/D shift button on the shifter works OK, shifting the tranny in and out of O/D, for about 10 miles. Just about the time the tranny fluid gets hot. Then it will not work the rest of the day. The tranny shifts great otherwise and I know for a fact the fluid is not getting hot. The temp sensor may have failed and is telling the EEC that the fluid is too hot and will not let it go into O/D.

What do you think?

Ed Springer

90 Black XR7 5-speed: 142,740 miles, 70mm TB, Fresh Air Intake, '94 Supercharger Upgrade, 36# injectors, 190 l/h fuel pump, 5% SC Pulley, Raised SC Top, I/C Fan, Under drive Pulleys, Headers, Magnaflow Muffler (no cats) with stock resonators, 3:27 Gears, Rear Spring Air Bags, Ripper Shifter, 73 C&L MAF, Magnacore Wires, NGK Iridium Plugs, Royal Purple Synthetic Lubricants.

94 Red SC Auto: 93,660 miles, 70mm TB, Fresh Air Intake, Stock 90 SC Pulley, 38# injectors, 190 l/h fuel pump, Raised SC Top, I/C Fan, Under drive Pulleys, Headers, Raven Muffler (no cats) with stock resonators, 3:73 Gears, 73 C&L MAF, Magnacore Wires, NGK Iridium Plugs, TRANSGO Shift Kit, Haydon Auxiliary Transmission Cooler, ProTorque 2500 TC, Tokico Struts & Shocks, Royal Purple Synthetic Lubricants, American Racing 17” Sniper Wheels, Michelin Pilot Sport A/S, dynode 235 RWHP at 315 LB-FT. Torque.
 
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