Member Since: 23 Sep 2019
Location: Richmond
Posts: 118
Transmission fault limited gears u0402-94
Hopefully someone can help me with my transmission fault.
Transmission fault limited gears available appears on dash sometimes it takes 10 or 20 miles, sometimes much less.
The car drives as if it cannot properly change up into the next gear. The revs drop as it tries to change, then go back up again, whilst staying in the same gear.
Also if I drive in sport mode it sometimes looses all gears, until I put the lever back into drive.
Normally when you move the shifter from drive across to sport mode the D on the dashboard changes to Sport and shows the gear selected. However when playing up the dash goes from displaying D to not displaying anything at all in Sport mode.
Along with this fault code U0402-94 invalid data from transmission control module. I dont know if this is related to the limited gears fault or not.
The iid tool I have does not recognise the transmission in live data or ecu info. I tried the iid tool on another vehicle and it recognised the transmission so I presume the iid tool is working correctly.
Thanks John.
16th May 2021 7:51 am
aja4x4
Member Since: 14 Apr 2019
Location: Westbury
Posts: 2463
The fact the lld is not comunicating with the transmission would lead me to think its a bad conection somewhere.
I would start by checking the wiring plug on the gearbox and the wiring plugs behind and under the battery.Andrew
D3 2.7tdv6 2005
D4 3.0 SDV6 Commercial died and gone to LR heaven
D5 3.0 SDV6 HSE
16th May 2021 9:53 am
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10742
yeah check the wiring, particularly the twisted yellow CAN wires.
Don't rule out a fault with power and ground connections
16th May 2021 11:39 am
johnhorgan
Member Since: 23 Sep 2019
Location: Richmond
Posts: 118
Aja4x4 and Pete K
Thanks I have checked the plug on the transmission, the pins are all looking good and lined up when plugged in. Can you tell me which pins to check for voltage / earth, and ignition status ?
Can you explain how to test/check can wires ?
(On the gearbox plug and on the transfer box)
Are there any other plugs to check behind the battery or anywhere else.
John.
16th May 2021 8:13 pm
johnhorgan
Member Since: 23 Sep 2019
Location: Richmond
Posts: 118
I meant gearbox plug and transfer case control unit plug.
16th May 2021 9:17 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10742
Check to see the wire insulation has any lumps in it.
purple with stripe +
green/white IGNITION (same colour is also diagnostic !!)
black -
17th May 2021 11:17 am
johnhorgan
Member Since: 23 Sep 2019
Location: Richmond
Posts: 118
I have checked continuity on each wire between each end of the transmission control unit plug (gearbox end and under battery). All wires have continuity and look in good condition- no lumps or anything.
I took apart all the other connections around the battery, transfer case module and engine control module and cleaned them with contact cleaner.
Since reassembly the vehicle is driving better, it now says "GEARBOX FAULT" periodically, (previously it said "TRANSMISSION FAULT LIMITED GEARS"), but is driving almost normally. Sometimes after the gearbox fault light chimes it no longer has 6th gear, so if doing 60mph and the light comes on it will change down to 5th even in automatic mode, whilst driving normally and changing gear at slower speeds, regardless.
All of the connections looked clean and in good condition, even before using contact cleaner.
The iid tool still cannot see the transmission control unit.
Any ideas what to look at next?
John.
19th May 2021 6:18 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10742
I'd suspect a mechanical fault with the gearbox (cracked drum)
but its odd you still have comms problems. Worth sorting out first.
19th May 2021 7:03 pm
johnhorgan
Member Since: 23 Sep 2019
Location: Richmond
Posts: 118
Click image to enlarge
Click image to enlarge
The only weird thing I could see was the 11.35 volts reading from the obd2 plug number 9 terminal.
Do you have any suggestions?
Second pic is from the gearbox transmission control module plug.
Regards John.
21st May 2021 8:04 am
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10742
what is the first pic ?
Did you confirm you had an ignitiion supply at the gearbox ?
21st May 2021 10:30 am
johnhorgan
Member Since: 23 Sep 2019
Location: Richmond
Posts: 118
First pic is the obd2 plug.
Yes I did confirm battery voltage to the gearbox at pin 9 the ignition supply red wire. Although there was only 11.35 volts at the red wire pin 9 at the obd2 plug. However everything seems to work through the obd2 plug, apart from no transmission ecu listed anywhere. It does not show it even to as not fitted, no mention.
21st May 2021 6:32 pm
johnhorgan
Member Since: 23 Sep 2019
Location: Richmond
Posts: 118
Finally figured out the problem, I eventually managed to find transmission ecu.
I must have been pressing the wrong buttons or something just as stupid !
I went to tool config, find ecus and it appeared !
John.
22nd May 2021 12:55 am
aja4x4
Member Since: 14 Apr 2019
Location: Westbury
Posts: 2463
Thats good but are there any fault codes relating to your issue?Andrew
D3 2.7tdv6 2005
D4 3.0 SDV6 Commercial died and gone to LR heaven
D5 3.0 SDV6 HSE
22nd May 2021 6:54 am
johnhorgan
Member Since: 23 Sep 2019
Location: Richmond
Posts: 118
Yes there is P0741 Torque converter clutch solenoid circuit performance or stuck off.
I had problems previously with revs fluctuating by a few hundred rpms, when at 60mph on a constant throttle, and when going uphill at 30 mph on a constant throttle.
There were no fault codes listed for this problem.
I sent the torque converter away to be reconditioned.
I rebuilt the gearbox changing clutches and bushes and rubber seals.
I ordered solenoids as well but they had not arrived.
I suspected the 4th 5th and 6th gear solenoid playing up, so I swopped it with the solenoid next to it, the torque converter clutch solenoid.
When I test drove the vehicle after reassembly the rev counter fluctuation had disappeared.
That was when the torque converter clutch solenoid P0741 reared its head.
Now I have replacement solenoids, hopefully changing them will cure the torque converter clutch P0741 problem.
22nd May 2021 6:05 pm
johnhorgan
Member Since: 23 Sep 2019
Location: Richmond
Posts: 118
My new set of solenoids finally arrived.
Thankfully fitting them resolved all of the gearbox problems.
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