Chapter 5
Jeep AW4

Transmission Overview
Jeepís AW4 transmission is actually built by Toyota; itís the same as the A340E transmission that Toyota uses. It has two shift solenoids and a lockup solenoid that ground through the valve body; the computer provides 12 volts to energize the solenoids.

Thereís no way to access diagnostic trouble codes on Jeeps without a scan tool; in fact, many of the aftermarket scan tools canít even access these codes. In some cases, youíll need a dedicated scan tool to read any codes in memory.

Terminal Identification
Hereís a breakdown of the individual connector terminals:

Shown from the terminal side of the transmission connector.

Checking the Shift Pattern
Hereís how to connect your signal box to the transaxle connector, to check the signals from the computer to the transaxle:

Backprobe the terminals with the harness connector still connected to the transaxle.

This is the shift pattern you should see with your signal monitor:

The far right LED indicates the signal to the converter clutch (TCC) solenoid.

Forcing the Shift
Hereís the manual shift pattern you can expect with the transmission in failsafe:

Hereís how to force the AW4 transmission to shift electrically:

First Gear
In First Gear, only shift solenoid 1 receives power.

 

Second Gear
To shift into second gear, the computer adds power to shift solenoid 2; both solenoids are energized.

Third Gear
To shift into third gear, the computer releases shift solenoid 1; only solenoid 2 receives power.

Fourth Gear
To shift into fourth gear, the computer releases power from shift solenoid 2; neither solenoid is energized. The additional gray wire is the power feed to apply the converter clutch.

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