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AW4 Defaults to Indicated Gear

X

xj upnovr

NAXJA Forum User
Location
Darlington MD
I'm on my fifth XJ. Was a member here back in 2003 but gave up my XJ to Dad. 1996 Country, now mine again.

Sometime during his use of it, the AW4 began to stay in the indicated gear only, and lost lockup. After perusing the many threads about the AW4, I realized that without a code in the PCM, the TCU must at least be functional. Which leads me to somewhere in the harness to the trans maybe? I completely disassembled the valve body and tested all the solenoids, so I know internally it's in top working order.

Anyone else have this 'Tiptronic' shift condition and how did you solve it?

I'm hoping it's a chafed wire or loose connector, but looking for more info before I start tracing wires and checking voltages.


cheers- and can't shake the XJ disease.....

:us::us:
 
You probably blew a fuse or your TCU is dead. On a 96 you can do basically whatever you want with the trans control system and the ECU will not throw any codes. It MIGHT throw a code if you completely unplug the TCU but I doubt it.

97 and later are the ones that get more picky about the TCU electronics being functional.
 
kastein said:
You probably blew a fuse or your TCU is dead. On a 96 you can do basically whatever you want with the trans control system and the ECU will not throw any codes. It MIGHT throw a code if you completely unplug the TCU but I doubt it.

97 and later are the ones that get more picky about the TCU electronics being functional.
Click to expand...

Ken, do the 91 to 96 XJs still have the TCU fuse up under the passenger side kneebar wrapped in yellow tape like the Renix models did?
 
I'm honestly not sure. I never had that problem on mine so I never went looking for a fuse :laugh2:
 
I'll double check the fusebox and look in the FSM for a possible in-line fuse and its location.

I have a TCU from both a 93 and 92. I'm guessing either would work in a 96?

Thanks much for the info!


Cheers-
 
Last edited:
Perhaps the OP should take a look up there then. We used to find the fuses good, but corroded enough so that no power flowed to the TCU. I have a sneaking suspicion the fuse is there.
 
Seems I have a 10-amp minifuse in slot 21 of the engine compartment fuse block.

There might be another in-line fuse in addition to this one?

:wow:
 
Below that little diddy box below the glove box poke your noggin up under there. The TCU is mounted up there on a metal bracket. Look for an inline fuse in the wiring wrapped in a yellow tape. I'm kinda thinking it's there even on your year..
 
Well this is crazy. Blown 10-amp fuse in the underhood fusebox. New one solved all. Wow. Never would have thought. Shifts perfectly, and the lockup is back.

Thanks to all who replied and pointed me in the right direction. I hope to return the favor many times over on here.

Well I guess I have a really clean valvebody now..... not a completely wasted effort !

If I could figure out how to post photos of the VB apart I would.
 
The real question is...... why did the fuse blow in the first place.
 
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