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HELP! 97 Disco immobilizer

4K views 12 replies 6 participants last post by  AAXD 
#1 ·
My 97 Disco will not start. I was washing under the car and it ran rough when I started it back up. I got it half way across the yard and it died all together and now has no spark and the fuel pump will not turn on which leads me to believe something has happened with the immobilizer. I opened the hood and blew everything off with air to dry out any wet connections but to no avail. My 96 Discovery did the same thing but the problem was cured by pushing the unlock button on the remote. The service manual says something something about a manual code entered by the key. I have a code written down but I am not sure how to activate it. Any help is appreciated as the disco is my daily commuter. Thanks in advance.
Colin
 
#2 ·
Or it could be the multirelay box. It also controls the fuel pump. On my 96 it is located on passenger side fender. It is a black, wedge shaped box. Open the cover blow water out of the relays inside and it should start. Another point was the ECU itself. Water got in through the multiplug. Unplugging the ECU, blowing waters out of the plug helped. Eventually I sealed both and no problems with water since. Hope this helps.
 
#3 ·
Will unplugging the ECU cause any problems? I suspected water might have gotton in somewhere near there. I took the relay box off and sprayed wd40 on the plugs but i didnt actually open it. I'll let it dry overnight then check it in the morning.
 
#5 ·
AAXD said:
My 97 Disco will not start. I was washing under the car and it ran rough when I started it back up. I got it half way across the yard and it died all together and now has no spark and the fuel pump will not turn on which leads me to believe something has happened with the immobilizer. I opened the hood and blew everything off with air to dry out any wet connections but to no avail. My 96 Discovery did the same thing but the problem was cured by pushing the unlock button on the remote. The service manual says something something about a manual code entered by the key. I have a code written down but I am not sure how to activate it. Any help is appreciated as the disco is my daily commuter. Thanks in advance.
Colin
Only the dealer can reset the immobilizer, it happened to my on 96 DI and I had to take it to the dealer.
 
#6 ·
AAXD said:
My 97 Disco will not start. I was washing under the car and it ran rough when I started it back up. I got it half way across the yard and it died all together and now has no spark and the fuel pump will not turn on which leads me to believe something has happened with the immobilizer. I opened the hood and blew everything off with air to dry out any wet connections but to no avail. My 96 Discovery did the same thing but the problem was cured by pushing the unlock button on the remote. The service manual says something something about a manual code entered by the key. I have a code written down but I am not sure how to activate it. Any help is appreciated as the disco is my daily commuter. Thanks in advance.
Colin

AAXD..i wonder if your problem may not be in a different area than the immobilizer. The security ecu communicates with the engine ecu and tells it "all's well, you can start"...if you had rough running prior to it dying altogether, it might be another problem. Reason being, the ecu signal is pretty much ok/ or not ok..not much in between.
You say you were washing underneath the car...i'd guess you may have gotten the crankshaft sensor wet.
It's not uncommon for this to happen with sensors that are on the verge of dying anyway.
good luck
 
#7 ·
The only other problem I had been having with the car prior to it refusing to run is, while on the highway, the speedometer would fluctuate and jump all around at steady speed. This would disengage the cruise control but I would have no problems driving normally. I drove the car 180 miles on the highway yesterday and it did this twice. The tach also doesnt like to come alive until the car is warm and yesterday while it was runing rough I got no signal from the tach whatsoever. Could it have something to do with the vehicle speed sensor? I've heard these can keep the truck from starting.
 
#8 ·
Sorry, that was me logged in under dads name on that last post
 
#9 ·
Has anyone encountered a similar problem before? I am almost convinced it has something to do with the security system.
Some specifics on the problem:
1. The key does not engage the started until about 5 seconds after turning the key to the II position, when it does crank, there is no spark but it cranks fine.
2. The fuel pump does not turn on when the key switch is energized. Dad jumpered the pump and it worked fine. I checked all fuses and relays and ECU for evidence of water and found none. Also sprayed all underhood connections with wd40. Could disconnecting any plugs have triggered the security system somehow? The service manual says something about disarming the immobilizer using a sequence of key switch turns, remote button pushing and entering something called a EKA (Emergency Key Access). It says to consult the owners manual for how to do this but after searching high and low I've found nothing. I do have a piece of paper that the previous owner had that contains the radio code and some kind of key code(I'm assuming it's the remote code) Can anyone shed any light on this problem or tell me how to go about entering the EKA? Thanks
 
#10 ·
AAXD..after giving your problem more thought, i'm starting to think the engine ecu might be the problem after all. The engine ecu on the 97 disco is located in the engine compartment, along the back edge of the passenger fender, where the fender meets the firewall(if my memory is correct). These are very prone to water ingress. The ecu should have a plastic water shedder cover over it, held on by two fir tree clip type fasteners. Pop these off, and you'll see the top of the ecu. Three plugs on top, and two small bolts,(8 mm) and you can slide it up and out. You should have no problems removing the connectors and removing the ecu , as long as you do this with the battery disconnected, there will be no ill effects. If your brave enough, you can remove the torx bolts that hold the ecu side covers on..then you can inspect the circuit bords for any signs of water or long term corrosion. PLEASE BE WARNED..typically ecu cover removal is done with an anti-static mat and grounding strap, as the electrics can be damaged by static discharge, although this is uncommon(use of the mat, and damage caused by not using it are both uncommon)
The tach not reading correctly, or sporadically, is usually an indication of the alternator beginning to fail. The tach signal comes directly from the alt, and this is pretty common.
You're right, the speedo bouncing around is , most likely, the speed sensor. The speed signal goes directly from the sensor to the instrument cluster..from there, it goes to feed a couple other units, one being the cruise ecu, and this would explain the cruise dropping out on you.

It's unlikely that the tach and speedo issues are the cause of your no start.

You say that you have neither spark or fuel..this is a pretty good indication of some type of large scale failure.The fuel pump should run and prime the system when you turn the key to position 2, regardless of crankshaft position sensor.

The gems ecu serves as both the engine ecm, and the security ecu. Both operations occur in the gems unit.
A quick check of the gems enabling a start condition is to do this....let the car sit, with the key off, for at least ten minutes....get in the car and turn the key to position 2...take note of the check engine light on the dash ...if this illuminates, it usually indicates that the security is ok and enabled..if you get no check engine light illumination, this usually means the security system has recieved the correct code.

good luck, and let us know how you make out
 
#11 ·
Dang..i need to type faster...lol
The delayed crank is definately an indication of a mismatch in security codes.
That, along with a lack of check engine lamp lighting up, means you are correct..it's a security issue.
Unfortunately..gems ecu's are kinda famous for this(or, INfamous).
The only way to correct this, that i know of, is a trip to the dealer.
The dealer will perform whats known as an F-OUT on the security system of the ecu. This should prevent future problems with the ecu "forgetting" the security code.
Although, in some instances..it doesnt. It seems that some ecu's just like to do this from time to time, F-OUT or not.
 
#12 ·
I guess I'll call AAA in the morning. At least I finally know what the problem is. Out of curiosity, I removed the ecu and boy am I glad I did. the corner of the fenderwell where it meets the bulkhead had about a pound of mud built up and the bottom of the ecu was sitting in it. I cleaned it out and found a bit of body rust too :bawling: I removed the torx screws and pulled the circuit boards out and found the ecu was loaded with road salt and all sorts of mud and other crud. I cleaned it thoroughly with baking soda and water and then dried it with a hairdrier and reinstalled it and tried starting it with the same result. The outside of the ecu box was very rusty and the die cast part was heavily corroded but still intact. I guess a new ECU box is now on the work list. I'd encourage everyone to check the area under their ECU for contamination and buildup. I was lucky that mine hadn't eaten through yet but It might be a good maintenance check item for all disco's. I'll report back when the dealer takes a look at the computer. Thanks for all the help everyone.
Colin
 
#13 ·
Hey all, I picked my Disco up from the shop yesterday and she ran fine. Turns out the problem was a loose connection between the multi-plug and the fuel pump relay. Kinda frustrating as it was one of the first things I checked, but I guess I didnt get it tight enough. Removing my ECU was definately a new experience for me. I just wanted to stress how close it came to frying itself from crud ingress. I didnt take any pictures before I cleaned it but suffice it to say it wouldn't have lasted much longer had I not cleaned it out when I did. :mad: Anyone driving a Disco 1 in the northeast is encouraged to check their trucks out in the area around the ECU. Mine has been a New England truck since new and has never been off road. Goes to show what the Cr*p they put on the roads does to these trucks. Thanks everyone for the helpful posts.
 
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