Hypothetical question about ECU and such
- Thread starter mongosd2
- Start date
Rover De Land
Observer
Nobody posted this so I figure I should.. You dont HAVE to get the ecu reprogrammed. which costs money at the dealer to swap it in in a 96+ or whatever..
Just get the alarm ecu that goes with the ECM, they go together. I got both from a junkyard for eh bout 15$. Just remember keep the alarm ecu with it. There easy to change, alarm ecu is below the dash.
Just get the alarm ecu that goes with the ECM, they go together. I got both from a junkyard for eh bout 15$. Just remember keep the alarm ecu with it. There easy to change, alarm ecu is below the dash.
ArmyRover
Adventurer
Oh really we might be able to talk trade David:coffeedrink:
David Harris
Expedition Leader
Can you do that with the GEMS?
On the Bosch, once an ECU has been alarm enabled, it can never be turned off again.
Viggen
Just here...
If its anything like my 95 with the external alarm ecu, then no, you cannot. Everything goes through that stupid ********** ecu. You can remove it by grounding out the starting/ ignition system that goes through it but then you are going to lose things like your horn, among others.
ipgregory
Adventurer
On a GEMS there is a setting that tells the ECU whether to use the Alarm Sync function or not. In normal mode (on) the GEMS ECU requires a signal from the correct previously synced Alarm ECU when you turn on the truck or it won't provide a spark and stops the truck from starting and running (this is the immobilizer feature for the alarm). When turned off it doesn't disable or do anything to the Alarm but it does stop the immobilization function. The GEMS ECU will allow the truck to start and run irrespective of the Alarm state as long as you can fire the starter and have power to all the right engine circuits.
I had the GEMS ECU replaced in my 98 D1 under warranty and didn't know that the dealer disabled the Alarm Sync function when they fitted the new one because they said they had seen a lot of instances of the 2 ECUs losing sync due to wiring issues and stranding vehicles. I found out when I was rebuilding my 96 D1 (including a new Alarm ECU) and my 98 ECU would start the truck whereas my (as then) unsynced 96 ECU wouldn't. Drove me nuts trying to work out why until I took the 96 to the dealer to have the new Alarm ECU programmed and they told what they had done to the 98.
It's a function in TestBook so I guess it's available to other 3rd party systems like Rovacom and so on. If you have access to a Rovacom or similar then the 10AS Alarm ECU is also programmable and you can enable or disable various functions but you can't easily remove it. If you have a 'spider' installed (not all trucks do) then it may interupt the starter wiring when the alarm is on but I am not sure (been a while since I looked at the circuit diagrams). I don't think many (if any) NAS trucks have the spider though.
I had the GEMS ECU replaced in my 98 D1 under warranty and didn't know that the dealer disabled the Alarm Sync function when they fitted the new one because they said they had seen a lot of instances of the 2 ECUs losing sync due to wiring issues and stranding vehicles. I found out when I was rebuilding my 96 D1 (including a new Alarm ECU) and my 98 ECU would start the truck whereas my (as then) unsynced 96 ECU wouldn't. Drove me nuts trying to work out why until I took the 96 to the dealer to have the new Alarm ECU programmed and they told what they had done to the 98.
It's a function in TestBook so I guess it's available to other 3rd party systems like Rovacom and so on. If you have access to a Rovacom or similar then the 10AS Alarm ECU is also programmable and you can enable or disable various functions but you can't easily remove it. If you have a 'spider' installed (not all trucks do) then it may interupt the starter wiring when the alarm is on but I am not sure (been a while since I looked at the circuit diagrams). I don't think many (if any) NAS trucks have the spider though.
David Harris
Expedition Leader
So in effect this would be equivalent to disabling the alarm except for the audible part (it would still honk)? The fuel circuit wouldn't be cut though, since this depends on the engine ECU as a partner, correct?
David
ipgregory
Adventurer
Based on my experience with my trucks and the research I did (albeit a long time ago now) then yes on GEMS D1s and GEMS D90s at least the truck will start and run with the sync disabled and that 'unlocked' ECU can be moved from truck to truck to at least start it and run. You may get other problems like an out of sync IACV or codes because of differences in the EVAP systems or when shifting between stick and auto trucks but the truck will run and get you home. If you have a spider installed then it may not as the spider may cut some of the circuits needed to start or run the engine. Non-Spider the alarm will still opereate the door locks, honk the horns and flash the lights but it can't stop the engine from starting.
GEMS P38s are probably a different story because of the BECM integration and electronic transmissions.
GEMS P38s are probably a different story because of the BECM integration and electronic transmissions.
David Harris
Expedition Leader
Thanks very much for the info! No spider on my early 1996, so good to go! BTW: Thanks Mongo for starting this thread!
David
Viggen
Just here...
My 95 does and so will your 96. It killed my truck due to bad connections in the alarm ecu. Replaced it and everything works as it should now. The alarm ecu grounds the ignition system. It controls locks, alarm, horn, lights and ignition. Look under the glovebox. Youll see a little black bow with two connectors: white and black. Thats your alarm ecu. Disconnect that and your truck will not run. You need to ground the system out by running one of the connectors to a ground and then itll work but you will lose things like your horn.
David Harris
Expedition Leader
No spider on my 96. I pulled the dash and it doesn't have one. Mine's an early SD and was spec'ed without it. No keyless entry either. BTW: Your 95 doesn't have a spider either. The alarm ECU isn't the same as the spider which is a secondary system added to most 96 and later Discos. It's located over the heater core under the radio/climate control on the dash.
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ipgregory
Adventurer
NAS 94-95 and 96-99 should be completely different trucks. 94 and 95 have the 14CUX engine managment system (has a distributor and is sometimes reffered to as an OBD I if it has the little black box code reader), 96 on are GEMS (has coil packs, no dizzy and has OBD II). 96 Has a Lucas 10AS alarm ECU fitted as standard (green box) even if the truck has no remote locking and may have an option called a spider fitted. The spider is an addition to the basic alarm ECU that functions as a circuit breaker to physically 'cut' the circuits to various things when the alarm is armed (cant remember what 'things' without going back over the diagrams). Its common in European trucks but I haven't come across a NAS truck that had it yet that I know of (not that that means much).
This is the model year by the way not the date of manufacture. Some 96 trucks may have 95 build dates on the sticker.
To confuse it even more. 97 NAS D90s also have a 10AS Alarm ECU Installed behind the dash but have no alarm function as standard (although with some work it can be enabled). Its there to sync with the GEMS ECU and allow the truck to start. They also have most of an ABS system but without the brake modulator and any way to control the brakes. Thats there to enable connection between the wheels and the GEMS ECU for the Rough Road system so it knows when to 'ignore' the knock sensors on rough terrain.
This is the model year by the way not the date of manufacture. Some 96 trucks may have 95 build dates on the sticker.
To confuse it even more. 97 NAS D90s also have a 10AS Alarm ECU Installed behind the dash but have no alarm function as standard (although with some work it can be enabled). Its there to sync with the GEMS ECU and allow the truck to start. They also have most of an ABS system but without the brake modulator and any way to control the brakes. Thats there to enable connection between the wheels and the GEMS ECU for the Rough Road system so it knows when to 'ignore' the knock sensors on rough terrain.
David Harris
Expedition Leader
Interesting info. When I pulled the dash to my 96 I fully expected to find a spider, but now that you say that you haven't seen one in NAS trucks, maybe my truck isn't so unique in that way. However, when I checked my VIN with LRNA, they said that it was very early and was probably a hybrid 95/96 in terms of specs. It's right on the crux of the 95 VINS, but is a GEMS OB2 engine.