Toyota A750E/F with Multiple Solenoid Circuit Faults

Oct. 31, 2014

Toyota Tundra, 4Runner, Tacoma, Sequoia and FJ Cruiser equipped with the A750 transmission may exhibit a complaint of multiple transmission solenoid electrical circuit faults set.

Wayne Colonna

Toyota Tundra, 4Runner, Tacoma, Sequoia and FJ Cruiser equipped with the A750 transmission may exhibit a complaint of multiple transmission solenoid electrical circuit faults set. Typically, to have multiple solenoid electrical faults indicates that there is a power loss or ground problems, possible compromised wiring harness (pinched, broken or melted0, or a connector is not plugged in all the way or completely disconnected. In this case, the cause may be, a bad weather pack seal on the harness side connector of the transmission case connector allowing moisture to corrode the male terminals and or deteriorating them. It is not uncommon to remove the external harness connector (female) and see the male terminals from the case connector, as shown in Figure 1, still stuck in the harness connector when this happens.

To correct this condition, replace the transmission case connector, which is part of the internal harness, and clean the terminals in the female external harness connector. Install a small amount of dielectric grease into the connector and a small amount of silicone sealant on the weather pack seal to prevent moisture.

Internal Harness (04-4Runner, Land Cruiser): 82125-35130

Internal Harness (05-Sequoia, Land Cruiser, Tundra, Tacoma): 82125-35150

Note: Contact your local dealer for vehicles other than shown above.

About the Author

Wayne Colonna | POWERTRAIN PRO Publisher

Wayne Colonna is president of the Automatic Transmission Service Group (ATSG) in Cutler Bay, Fla., and a frequent speaker/instructor for transmission training around the globe.