Transmission Fault

[Jonsey]

My Disco 3 2006 tdv6hse goes into fault mode when towing caravan up steep hills this maybe after adding an Ledconnect module . Has anyone had a similar problem? Transmission has been overhauled befor and after fault.

[PaulGOz]

I think you would need to read the fault codes. I have had transmission errors a few times it can be the result of numerous other things upsetting the transmission computers and not actually be transmission related. Much to the amusement of my Patrol buddies I stop and reboot and it seems to clear intermittent faults. The Patrols just blow up without any warning much less convenient IMHO.

[CATS]

Also note that the manual state, mine anyway, that when towing at speeds of lower than 40km/h for some time that it is best to do so in low range. Might be part of your problem?

CATS

[NavyDiver]

Do you have electric brakes on the trailer? It might be the trailer but first check and eliminate the issues that commonly cause faults in your car first being brake switch and stop light globes. Have you put LED globes in the brake lights on yours?

[Jonsey]

Thanks for replies. Low range not needed as towing well over 40kph.
No I have not changed my globes and they all work OK the only thing that changed was the addition of LED module to eliminate pulsing on caravan. All the experts ( auto electricians etc ) say this shouldn't bother the car. I will be testing again without module soon but don't like running around in fault mode. If it is not the problem it may be intermittent and come up again later and have nothing to do with the LED module.

[Jonsey]

Fault Code U0402-94 came up at dealers .

[sheerluck]

I was under the impression that U prefixed faults were communications errors and could normally be ignored. However, that one comes up as "Invalid data received from transmission control module"

Don't know. :(

[jonesy63]

Is there any corrosion on the TCM connectors - after engine bay cleaned by pressure cleaner or deep water crossings?

[Graeme]

Fault Code U0402-94 came up at dealers .Did the dealer then suggest any possible causes?

[Jonsey]

Thanks for replies.Sorry what and where are the TCM connectors ?
No the dealer had no suggestions as would imagine I am not keen on spending another $3000 on another mechatronic on a maybe .

[Jonsey]

If TCM connectors were corroded wouldn't it cause fault codes all the time not just under load when towing caravan?

[Graeme]

I would confirm with the dealer that the gbox software is up to date and if not, get it updated before considering anything else.

Are there any engine fault codes stored? The engine not performing properly can trigger gearbox faults especially when loaded or towing.

[herrBlick]

Here's a link to what I've been dealing with ....clean the MAF sensor
http://www.aulro.com/afvb/showthread.php't=181045

[Jonsey]

Yes dealer did a software update.

[Jonsey]

Tried towing up the same hill that caused Fault in transmission this time without Led module and the car ran fine. Doesn't make sense but will try a longer run soon ,happy if this is the problem.

[Blue C]

Tried towing up the same hill that caused Fault in transmission this time without Led module and the car ran fine. Doesn't make sense but will try a longer run soon ,happy if this is the problem.

I have an LED module for my off-road camper and have had no issues towing it up hills (high and low range) for 3 years (until yesterday). I also had my transmission flushed + metal pan about 3 weeks ago at 60,000km.

Yesterday whilst driving in manual mode (5th gear) up a steady moderate incline on SE Freeway in SA holding ~90-95km/hr without any warning appeared multiple errors including engine, transmission/air suspension, park brake messages and "F" appeared in the gear selection display where "5" was previously. The suspension lowered. I pulled over and cleared faults with engine off /on and same problem recurred about 2km later- also cleared same way after waiting 5+ minutes at idle. Then drove using slightly more revs each gear (2400-3000) up the remaining hills. Initially I wondered if it could be something to do with the recent transmission service (as it has never done anything like this before). However this morning I found following fault codes using Hawkeye:

EMS:
1. P0087 : Fuel Rail / System Pressure Too Low
2. P000E:Fuel Volume Regulator control exceeded learning limit. Signal amplitude>maximum.
DTC:
U2023 : Fault received from external node- engine torque information:Signal invalid
U0100: Lost communication with ECM/PCM "A"-missing message.

I wondered if the P0087/P0003 faults could be related to the DP chip I have whilst engine is under increased load? If so and a remap was done instead would the threshold for "exceeding the learning limit" be increased? Any comments appreciated. Regards, David

[gghaggis]

I wondered if the P0087/P0003 faults could be related to the DP chip I have whilst engine is under increased load? If so and a remap was done instead would the threshold for "exceeding the learning limit" be increased? Any comments appreciated. Regards, David

Towing a sizable load for long periods with a tuning chip such as the DP Diesel chip is NOT a good idea. Yes it will cause faults - I don't think the car can calculate the correct working envelope and assumes it's fueling rate is wrong for the detected EGT's. A good remap (if requested that towing usage is taken into account) should be able to circumnavigate this issue.

Cheers,

Gordon

[Blue C]

Thanks Gordon. That's what I expected you might tell me! I originally fitted the DP chip as I had it new from a prior vehicle and for around $300 had the software configured for the D3 (same DP31 chip). Obviously cheaper at the time than a remap but I can see I'll have to make a decision now on whether to simply go without the chip, or remap the D3, or wait for a MY14 D4 perhaps?:)

[Graeme]

1. P0087 : Fuel Rail / System Pressure Too Low
2. P000E:Fuel Volume Regulator control exceeded learning limit. Signal amplitude>maximum.

These messages are showing that the fuel pump couldn't maintain sufficient fuel rail pressure even with the regulator fully open. Was there lots of of black smoke out the exhaust?

[Blue C]

Sorry Graeme I don't know. Friends travelling with us were in front and I didn't notice anything unusual in the mirrors. It has rarely blown black smoke to my knowledge. I have always left the DP chip on standard factory setting (no. 5: range 1-9) which is reasonably conservative (said to =~166kw & 492nm torque). Going back 2 yrs it did it on same section of hills and you may recall we blamed a faulty connector on the LLAMS cascading up to multiple faults. I will see if I can find the emails re faults back then but perhaps the DP chip was the cause then too. Is it reasonable to assume that if I took the chip off the fuel pump could keep up??

[Graeme]

My interpretation of the messages is that the fuel pump cannot maintain pressure at the current fuel usage and fuel pump revs suggesting possible excessive fuel usage but maybe not, just using more fuel to get more power from the engine than what the pump was configured to provide. Dropping to a lower gear for the same power production would have the fuel pump turning faster and probably not using much more fuel and possibly even less fuel along with staying away from higher EGTs. Removing the DP chip would be one option but using a lower performance setting might be a good compromise. I generally work my (stock) 3.0 lower in the rev range on the basis that the engine is being operated within LR's limits but sometimes drop a gear to tax the engine less, with the climb away from Adelaide towards Murray Bridge a typical section of road.

[Blue C]

Thanks Graeme
That all makes sense. Interestingly both this time and 2 yrs ago the faults occurred whilst towing during climbing hills after driving all day in warm temperatures (32 degrees + headwind for 4-5hrs on Wed this week). I wondered if holding a higher gear also raised the EGT's above a certain threshold that was possibly the final trigger for the faults to cascade?? However no fault for EGT was logged. I also found a DP Chip customer info sheet recommending lower setting ( 2 instead of 5) if limp home mode triggered more than once (in my case twice on 1 day). I haven't yet decided which way to go (lower setting or removal). Regards, David