DiscoII Td5 "low range" problem

Hi guys,

I've got a weird problem on my 2004 Disco Td5 Auto - I've noticed a substancial drop in fuel economy and power on uphills.

Had the system checked and found that the computer is "stuck" in low range although the vehicle is in high range. Test the sensing switch on the transfer case, but there's not problem. Seems that the gearbox ECU sees the vehicle as in high range, but the main ECU sees it as in low range and hence alter the computer mappings accordingly.

I found traces of oil on the wiring harness at the ECU so there's the problem, but wasn't this supposed to be rectified on later model Td5s?? The vehicle is just out of warranty so the dealers isn't willing to fix this problem - although its a Land Rover design flaw!

What now?

It looks to me that you need to replace the wiring loom. About £37 + postage for the loom, £3-5 for an electrical contact cleaner and about 1 hour of work or something close to £200 at the stealership or something in between through an independent.

did cleaning the oil out of the loom fix the problem?

I cleaned the big red plug at the ECU etc , but no improvement yet.

Anyone got a part number for the wiring loom?

Land Rover South Africa want to charge me R9000 (+- £650) to replace the loom which is absolutely insanity.

I'm going to put a drip point on the loom to see if it makes a difference. I figured at the lowest part of the loom between the rocker cover and the ECU I could put a rubber grommit glued on with a drop of silicone as a kind of 'drip point' to stop oil getting past. It can't hurt to try..?

However, in your case it looks like this may not be the cause of your original problem.

George, LR SA wants to charge you that much because the tech note says that not only the injector harness needs to be changed but also the engine harness.
But there are good chances for you to be lucky and get away with a careful cleaning of the engine harness.

The injector harness is part# AMR6103. You can find it OEM or aftermarket. All major online shops have it. You can find it on ebay too ( example - delivered worlwide ).

P.S. Here is one place where you can find info: Web Rover , check the link on the bottom and you will find the tech note.

P.P.S: Indeed, the cause of your original problem might not be the oil in the loom, but you need to sort that asap and go from there.

Thanks very much for the info. I checked on Microcat for the parts, but which one is it that has the big red plug to goes into the ECU? I can't identify it via any of the harness pictures.

My problem should hopefully be sorted out with a harness problem somewhere as the gearbox ECU passes on info to the main ECU and the gearbox one sees the vehicle correctly as in high range (so no mechanical problem luckily)

From the technote it seems as if the injector harness is the big bad guy responsible for the notorious Td5 oil-in-the-harness problem - but could have now 'contaminated' the whole lot I guess...

Some pictures of the same problem at this link: from Landroverclub Luxembourg (check the very end too).

You got it right, the injector harness is responsible for the mess.

It's the "engine harness" the one that has the plug that goes to the ECU, part# YSB108710, see attachment.

Thanks very much. The Disco went in to the dealer I bought the vehicle from today (non LR agent specializing in LRs) and they'll repair on their cost since I got the Disco from them 3 months ago in that condition. Phew...

I looked at those pictures in the link you sent - they look very familiar ;-)

Ok, the injector harness has been replaced and engine harness cleaned out, BUT, it seems as if this problem wasn't the answer to my problem.
According to the computer the gearbox has a vin nr of xxxxxxxxx (cleared by some or other knitwit at Land Rover) hence the communication between the ECUs isn't what it is supposed to be. Booked in at the local LR dealership on Monday to set the vin nr accordingly on the gearbox. Can only be done on the LR Testbook so Autologic or the other computer brands can't set this.

Had the vin number set on the gearbox and the problem is gone. ;-) Now also just going to have the injectors removed and cleaned as this could also apparantely improve consumption and power.

Thanks for all the help.

George said:

Had the vin number set on the gearbox and the problem is gone. ;-) Now also just going to have the injectors removed and cleaned as this could also apparantely improve consumption and power.

Thanks for all the help.

Click to expand...

Hello,

It seems I have the same OR similar problem... In my '99 LR Disco td5 the Engine ECO sees that the the gearbox is in "Low Range" while the Gearbox ECU recognizes it correctly as "High Range".

I have 30 sec. to 100 km/h (60 mph). I can not go faster than 125 km/h (~70 mph).

All engine sensors operate correctly, ECU doesn't have any errors.

Today I have tested it with Autologic and:

- there is a correct VIN number in the BCU,
- there is NO VIN NUMBER in the Engine ECU,
- the Engine ECU doesn't show some other date it should, like part number, version, date and so on,
- the Engine ECU shows "Low Range" while on "high" and vice versa,
- the Gearbox ECU doesn't have the VIN number either...
- in Autologic there is NO WAY to enter the VIN into any of them :-(

So... we have swapped the ECU from another Auto td5 (2003) and programmed it with the correct security, VIN and current date, accelerometer and so on...

In the Gearbox ECU there was still no VIN number.

After all this the Engine ECU recognized the Low/High Range correctly, BUT the car was running as before. What we have not done is entering to the new ECU the injector codes.

QUESTIONS:

- Do you think that incorrect injector codes may cause the car to be SO MUCH slow?
- Do you guys know any way to program my Gearbox ECU with the VIN number?

Best regards,

Filip

I had the VIN number programmed today into the Gearbox ECU and... it made no difference :-(

Still looking for a solution...