I own a 1993 Jaguar XJ40, 3.2 litre RHD in Australia. For some years I have been trying to find why the central locking does not work, however that is not the immediate issue here.

I had all the wiring exposed in the transmission and under dash left side looking for the central locking problem - again - however this time when I put it all back together, the starter motor won't work!!

Dash ignition lights etc come on normally but when the key is turned to Start, nothing - except the dash lights etc go out.

I can start the car by running a jumper wire from the ignition switch to the starter, so I doubt it is a starter motor problem.

My Owners Manual at page 26 states:

Can anyone tell me about the "Starter Motor immobilise", where I find it and how I reset it?

Getting desperate...............

Thanks

Bob in Oz

 

Hi Bob,
I'm not sure if this will help but, if you have put everything back together correctly then try removing the fuse for the security system and see if the car starts then.

If it does then replace the fuse and then try to restart the car.

I haven't got the diagram for your car so this is just a wild stab in the dark.

 

Hi Jim. The car has 66 fuses (from memory) in three fuse panels, left and right A Frame and centre consol.

There is no fuse specifically for a security system.

Bob

 

Ok Bob, I assume you have checked the fuse for the starter relay and the relay itself.

Could you be missing the ignition switched ground as you say the dash lights go off when you try to start.

 

In desperation I checked all 66 fuses, all OK.

"ignition switched ground"?

I can start the car if I run a jumper from the ignition switch to the starter. In the circuit is the transmission cut out switch (so it can only start in N or P), the ECU and four relays. Can't fault any of those.

Bob

 

I may have misunderstood but I'm not sure what you meant by not being able to fault the tranny switch, ecu and relay?

Did you check each component, i.e. check that they have 12v when ignition is on? I would start at the relay, check voltage and if it's there, jump the relay to see if it will start. Then go backwards through the circuit.

The other area that might be the cause is the connection block in the center console. Perhaps when you were troubleshooting your locking problem, a connection got loose? Both the rotary switch and the relay connect at this block, as shown in this marked up diagram.

xj6 starter.pdf

Cheers,

Allan

 

Thanks Allan. I checked the components by borrowing used parts from a Jag dismantler. The lesson learned from that exercise is that it seems no two XJ40s have the same components?

Yesterday for some inexplicable reason it did start four or five times, then back to nothing again. Can't think of anything we did that would cause the starter to work. It has been around two months we've been trying to fix the central locking, now this problem.

I suspect part of my original electrical problems was an after market alarm system installed by a previous owner, which we removed a year or two ago.

The "Starter Motor Immobilise" mentioned in the manual, does it exist and where is it located? It is not mentioned elsewhere in the Owners Manual and not mentioned at all in my after market service manual.

Aside from the excessively complex electrics it is a wonderful car in show room condition, but I'm running out of patience. My E Type electrics are so basic and simple..........

Thanks

Bob

 

Great looking Etype Bob.

Not to be too simplistic, but have you checked the connections on the starter.

If it has started 4 or 5 times then it could just be a loose or dirty connection.

 

Bob,

Part of the problem may be that Jaguar fitted different types of systems for different markets.

In the US a full factory alarm was fitted on 93-94 cars. In that system the security ECU communicates with the CPU via a serial data link. The CPU will then switch the output to the starter relay on or off (immobilise) based on the conditions. (As shown in the diagram above)

Other markets just had an immobiliser fitted but I'm not sure how that was connected as there may not have been a security ECU.

I'm not sure what type of system was fitted for cars down under? If it has a factory alarm, you should find the security ECU in the front left or right of the boot.

In any case I'm with Jim, if it started a few times, it really does point to a connection issue. One thing to check, very often the gear shifter does not make good contact in Park and Neutral until you jiggle it.

I would still methodically check inputs and outputs to each component in the circuit to narrow down the list of suspects

Cheers,

Allan

 

Sounds like the ignition switch itself is faulty to me. Had the same exact scenario on an older Audi where I wired a push button start switch to bypass it.

 

Hi
I had a similer problem after replacing fuses for my sport mode on my 1990 4.0
the car would not start on starter but all dash lights were on. I disconnected the battery for a few minuits and then reconected'and it started up straight away 'may be it needed a reboot that was 3weeks ago and still ok' worth a
try
Cheers

 

Thanks for all the comments. We've tested and discounted all the simple and normal check items - fuses, starter motor, loose wires, bad earth etc.

I may be getting somewhere.............

Next clue:

This module is under the glove box on the left hand side of the dash - remember, this is a right hand drive car:



The box contains four relays, numbered one to four on the cover above:
1. Door Lock
2. Door Unlock
3. Mirror heaters
4. Starter solenoid



If I press and hold in relay number 4 - large relay to the left of the circuit board - I can start the engine every time.

Obviously that relay is not getting power to close the points.

Any ideas why it is not getting power, or even where it gets power from?

Thanks

Bob

 

Using the diagram in post 6, if you follow back from the relay and electrically prove each line you should then be able to track it down.

 

Grrrrrrrr!! Right in the middle of amending my last post......



I missed the diagram attached to post 6, have it now, will print and look again tomorrow.

Bob

 

Bob,

Sorry, I probably should have made the link to the diagram a bit easier to see

Yeah the relay is where I would have started. If it just plugs into a base, pull it and check the pins for any corrosion, then check the the female pins and solder joints of the base. If all that fails, you may have a crack in the one of the PCB tracks (less likely).

This will probably also explain your central locking woes too

You can still get the DBC10008 new for about $100US or used on Ebay for $20US so either way should be an easy fix.

Cheers,

Allan

 

Thanks Allan. I'll go check all that this morning. Found a DBC10008 box on EBay for US$15 plus US$13 freight from San Diego (none listed on EBay in Australia) so bought it "just in case".

Wonderful car, but why are the electricals be so darn complex? More fuses and relays than a Space Shuttle!

I'll post the results - or more questions!

Bob

 

Allan's post # 6 above, in the attached diagram the "Transmission Rotary Switch" - is that this box:



Below the gear selector lever:



Or is it the rotary or half round switch on the side of the transmission????

I have two of the above boxes, the correct box in the car which has NINE (9) wires into the plug; and the above box dated 1996 has only FIVE (5) wires into the plug and does NOT suit my 1993 car.

FIVE wires into the plug does NOT suit my 1993 XJ40:




The diagram indicates I should get a circuit across Red/Orange and Green/Orange when the transmission is in Neutral or Park.

There are Red/Orange and Green/Orange wires into the above box. I can not get a circuit across any pair of wires on either box with the slide in either the Neutral or Park position - or any other transmission position.

1. Is the "Transmission Rotary Switch" this black box, or is it the half round switch on the side of the (ZF) transmission???

2. Can anyone help with a part number for the above black box with NINE wires into the plug???

3. Can anyone help with a part number for the half round switch in the side of the transmission???

I am reaching the stage where I feel like keeping the number plates and replacing what is in between!!!!!

I bought the box DBC 10008 at very reasonable price and will also buy both the correct black box above and the half circle or rotary box on the side of the transmission. If I must keep changing boxes until I find the problem, so be it!

I gave up on the XJ40 today and completed a couple final jobs on a ten year nut and bolt restoration of my 1953 Ferguson TEA20 tractor. That restored my faith in British engineering!!!!



That is a 60 year old British Ferguson TEA20 tractor with Standard engine, not the US TO20/TO30 with Continental engine. (The Ferguson engine is near identical to the engine in the Triumph TR2, TR3 and TR4 sports cars of the 1950s.)

I really appreciate the help you guys are giving. I live in a small Australian Outback town 300 miles from the state capital, a long way from any Jaguar expertise.

Bob in Oz

 

Hi Bob,

1. The rotary switch is on the side of the transmission. It is part 1 in this diagram.

Attachment 55635

2. The blackbox LNA6550BR is the linear switch for an X300. The correct linear switch for the XJ40 is DBC12395. (Though I still think the relay module is the culprit in your problem)

3. The rotary switch part # is DAC10868 (this is for the 4 litre model but I think the 3.2 uses the same gearbox so would imagine the part is the same)

Something that might be helpful are the parts lists and the electrical guides for the car. Go to this website and download them for free

There is other great info here too. The engine management diagnostic guide is very useful!!

Cheers,

Allan

 

Arrgghh, I was just looking at some other diagrams and it looks like there was NO rotary switch on the 3.2L gearbox?

Sorry Bob, I may have been steering you in the wrong direction I also suspect the wiring diagram now too as it was also for a 4 litre. I will try and find the correct one for a 3.2L. What is your VIN # is it before or after 667829? That will help find the right info.

Apologies again!!

Cheers,

Allan

 

Hi Allan. I really appreciate your help. Here is the Heritage Certificate details:

Make and model JaguarXJ40/XJ6 3.2 Litre

Body style Saloonright hand drive

Date of manufacture 17thFebruary 1993

Chassis number SAJ-JFALG3AJ677585

Engine number 9BPMNA 113137

Body number Originally:JB 056334/2Q 011094

Gearbox number Originally:1479934

Transmission Automatic

Exterior paint colour Flamencometallic

Interior trim colour Doeskin

Hood (soft top) colour NotApplicable

Original distributor JaguarAustralia Limited

Original dealer NotRecorded

Date of dispatch 15thApril 1993

First owner NotRecorded

Registration mark NotRecorded

When I click on Attachment 55635 in your link I get: "Invalid Attachment specified. If you followed a valid link, please notify the administrator"

DBC12395 does not come upon EBay, will need to do a little searching for a source.

Can you please post the URL?

It is 3.30 am and I am about to depart on a 500 mile business trip by road but I will check the gear box and post a response as soon as I can.

Thanks again for your help.