My lucky dip XKR which I bought last week and had transported to me has now been checked and found wanting. After waiting for a phone call from the garage which was looking into the RESTRICTED PERFORMANCE issue I am told that the ECU was not triggering the second fuel pump. This pump works but it does not get power to operate. It had been shorted out which at least allowed the car to be driven. This is the little fact the seller did not mention. So now I need a new (or other) ECU. Where to find one? Any ideas, anyone?
Part Number DENSO LNG1410AC made in Spain

Been looking at the ECU replacment threads and this looks ominous.

 

You sure its not a wiring issue? Obviously you have checked all fuses... and relays.. How was this worked out? Was it a code read? or an ECU test? And what year? If a second pump assuming 2002 or older.. I have this thought with mine about the second not being triggered....
I have yet to do this but think i need to.. put the pressure test on and then drive it with it on to see if the pump kicks in and I get to over 50 psi..

 

Hi, I do have a spare, working engine control unit you can have. As always one small catch, the part number I have, is slightly different than the one you have, the last letter is a D instead of a C.
I have LNG1410AD instead of LNG1310AC. I changed my ECU when I changed my engine from a 4.0 to a 4.2. I assume the letter difference might be this.
Please do some research and see if this will do and if it does I'll post it over.
Very, very best of Luck, Colin.

 

So the car won't start/run unless the relay for the second fuel pump is bypassed?


Please put the vehicle details in your sig:- 4.0L and 4.2L XKR are fuelled differently.

 

It is pointless to guess about parts and answer questions without MAKE,MODEL,YEAR.
VID block cars can get 'tricky'.
4.0 cars are much easier.

 

It’s my understanding that the 4.0 cars will run without the secondary (high demand) fuel pump functioning at all, but acceleration will be impacted without the second pump.

if that’s actually the case, the OP’s should start just fine without a functioning pump #2.


Z

 

"LNG1410AC" I guess is an AJ27, probably Euro'00/US'01 year?
- based on LNE - 99, LNF - 00, LNG - 01, LNJ - 03 (euro year, except 03 seems too late for AJ27?)
- 1410 I believe is ECU part number
- A is supercharged
- C is software/firmware revision

As suggested, I would eliminate all other possibilities before looking at the ECU, since they are very reliable, and if you swap it you will have to do an Immobilization setup to get the keys to work, etc. which requires Jaguar IDS tool.

If the fuel pump relay coil/wiring has failed, I would expect a P1646 diagnostic trouble code (DTC).
If the relay contacts/wiring have failed then there would be no code.
I believe fuses are #22- 20A for the relay contacts to the pump and #3-5A for the relay coil
Relay (brown) should be in the trunk fuse box

Checks would be the following, if I extracted the correct section...


The progression of the LNG series is, I think as follows,
where V9CA/V9D is the fuel parameter set, so possibly an "AD" would work instead of an AC but the fuel set seems different, or if not then again with IDS it would be possible to reflash the unit.
LNG 1410AC V9CA
LNG 1410AD VB8
LNG 1410AE VBA
LNG 1410AF VBB
LNG 1410AG VBB
LNG 1410AG V9CA

If the ECU power transistor is really confirmed to be blown, then I think it is T912, but unknown surface mount type, seems to be NPN, on backside of PCB, but I have no specs...probably generic so might be possible to replace with similar package size NPN part that has suitable specs to drive the relay coil. Or use a boost switch or injector duty cycle measurement device to trigger the second fuel pump instead, or replace the two fuel pumps with a higher capacity single unit.

 

Mine.too, but I'm not 100% clear on whether the RP happens if the second pump isn't forced on, or the car won't run without doing so.

 

I have worked on MANY cars with only the primary pump functioning.
I usually check the secondary pump in all my supercharged cars every once in a while by bypassing the relay to check for pump operation.

Many customers don't realize that the cars have 2 pumps and that their secondary is inop.

Just replace both if you need to replace any in the tank.

 

I am severely challenged by electrical systems designed after 1966. My 2002 XKR is the first car I have owned made after 1969.

Would you mind detailing which relay is bypassed, the primary or secondary pumps ? And what the process is for bypassing a relay ? Which pins arw
connected ? Can you believe I don’t know ?

Basic questions I know.

Z

 

Essential reading for 4.0 XKR owners:-

https://www.jaguarforums.com/forum/x...el-pump-85882/

 

Wow - so many people helping with this ECU problem. Very impressed - this is certainly an active group. I will try to reply to the questions. I have amended my signature to include details of vehicles owned - for this thread on the XKR it is a 2001 year with 4.0 l engine. I went today to speak to the garage owner where the car now waits for some action, and to bring back the ECU box which comes out easily enough. All fuses and connectons, relays etc check out okay, and the two pumps can be heard working when powered up directly. The car has done 162 000 km so the fuel pumps fall right into the failure time period but do work. Maybe they were replaced - who knows. I call it my lucky dip Jag as it came marked down due to the restricted performance tag. No manuals or service records supplied, but the car (apart from the fact it does not go) is in fine shape!
I was told no codes were retrieved, or retrievable. Is this an issue with that model XKR? I was told it is.


Cap'n Col - that is a very generous offer you made about your old ECU. My plan now is to work on the ECU to see if it is fixable, with assistance from a capable friend with electronics experience.
I'm looking now for pinouts and circuit diagrams. This may take some time!

Thanks again to all replying so helpfully.

 

Got my ECU back from the garage that diagnosed the problem. My plan is to put it back into the car and drive the car home again. I realize that fixing this Restricted Performance thing will take some time. So I'll pay the very fair bill for the work done so far, and see if it is possible to fix this ECU. I am not too optimistic, but i'll try to keep all informed (at least those interested)

In the mean time I have my brother in law travelling to Georgia early next week so Capt'n Col could I talk to you privately in taking you up on the offer for that ECU you have? I could give you an address to post it to, in Georgia... If we could somehow learn to fix these ECUs it would be a grreat help to many people. Fools rush in .......??

I'm hoping in the meantime to enjoy my Jag to 3000rpm (If it still goes)

 

Please ensure that the VCATS match.

You will also need to do an IMMOBILIZATION SETUP when the ECMs are swapped.(engine will not start until the replacement ECM is 'introduced' to the CAN bus)

 

Hi KRNW. I've sent a PM to your mailbox. Lets get this sorted asap. Catch you soon, Colin.

 

Hello Colin. Again, thanks for your help. I'll send you a private email soon. Today, with a friend experienced in electronics, I cut the warranty thread on the ECU box and had a look inside.,,Picture attached below. It looks like new - not bad after 25 years. I can't believe this thing is faulty, and respect the suggestions from others on this forum that these ECUs seldom give trouble. So back it goes in and further diagnostics to be done.

DENSO ECU LNG1410AC from XKR 2001 4.0 L

 

Really you need to test the second fuel pump relay output at the ECM wiring harness to see if it is being activated - just because the board looks healthy doesn't mean there isn't some tiny failed component somewhere. If it really doesn't work you will have to trace it backwards from the connector until you find the failed component.

I still think though the failure is more likely outside the ECM than inside - in other words rule everything else out first.

 

Thanks Dibbit. I have the car back. All seems well until 3000 rpm when the Restriction comes in. I agree with your comment about the cause of the RP being elsewhere than in the ECM. But the repairman was adamant that the fault is in the output from the ECM.
Do you know which is the pin for the fuel pump?
I need to find a pinout diagram for the 1410 ECM.
The good news is that the car goes well until 140 km/h

 

If you are trying to rev the engine in neutral, you will find it won't go over 3000 rpm - that is as designed and is not a fault.

You can download the wiring guide for your car here:-

http://jagrepair.com/images/AutoRepa.../jagxk2001.pdf

That is a link to the PDF file. Another member says they have had to register with a credit card to download files from that site, but it should just download without any kind of registration - there is a donate button on the site, but it isn't obligatory. The website is by a well known member on the forum, and I have been using it for years without any issues, but please report back if it doesn't work.

The electrical guide has every bit of information you need, including wire colours, connector pin numbers, module locations, fuse locations and ratings, even the make and model of connectors used on the wiring harness, so it's well worth studying.

 

I think the 3,000 rpm limit applies to the P (park) position also. Although I admit I’ve never had the need to test that theory ..?

Z