Bringing a 1995 Discovery back to life

[AndrewClarke]

Hi. I was given a 1995 Discovery and am trying to bring it back to life. Amongst the problems I have to resolve before I can get it safetied are:

- Code 17 (throttle position sensor) on code readout
- SRS light on

So dealing with these one at a time, is the best way to determine what the TPS issue is to test resistance across the range of the sensor? I think I just turn the sensor by hand and see if the ECU reads the proper variation in resistance? Is that the first step or is there something else/easier I should check first? I have a 4.0 Discovery parts vehicle as well but the sensor for that one unfortunately has a different plug system and I'm loath to start cutting wiring if I'm not even sure it's the sensor that's causing the problem.

SRS light: the vehicle was sitting for maybe 2 years with no battery, and I tried a bad battery before putting a new one in, so it seems like there's a very good chance it's just on due to low cranking voltage. However, a call into the dealer didn't yield a response so I'm not sure they can/will reset the SRS light. I just drove 2.5 hours to a Land Rover guy who claimed to have a computer to reset this, and then couldn't figure out how to interface with my vehicle so that was a frustrating five hours of driving for nothing, apparently. I've read every site I can find about how to find the serial link mating plug, but for the life of me I can't find it in my truck, anywhere. I've looked under the passenger footwell, driver's footwell, behind the glove compartment, under the passenger seat. Nothing. Could it be possible that it was actually just forgotten in my truck? I'd rather not just disconnect the light, but if it comes down to it that's what I'll do.

Thanks for any tips or ideas,
- Andrew.

 

[robertf]

Srs connector is behind the fuse box door. It's part of the obd2 plug on 96 and newer trucks so that's probably the cause of the confusion. Easiest way to fix it is replace the airbag "computer" with one that doesn't have a fault. Any discovery with 2 airbag sensors (each side of the radiator) is compatible. Later ones had a single sensor.

4.0 tps does not fit a 3.9.

 

[AndrewClarke]

OK thanks. When I'm back home I'll check my parts Discovery for SRS computer compatibility with this one.

 

[cosmic88]

...... I can find about how to find the serial link mating plug, but for the life of me I can't find it in my truck, anywhere. ......
- Andrew.

Are you trying to hook up to the main ECU? What software are you using for reading that OBD1 data?

If it is the main ECU, which will be able to show you all engine mgmt. info but not SRS faults, then that interface plug is located behind the right-hand foot well facia (pull the cardboard under glovebox and plastic panel on the far right). It is a white, five pin, male plug. Actually, there are only three pins in the plug and it is connected to a female with only one pin. This plug exits the main ECU harness relatively near the ECU itself.

 

[AndrewClarke]

Are you trying to hook up to the main ECU? What software are you using for reading that OBD1 data?

If it is the main ECU, which will be able to show you all engine mgmt. info but not SRS faults, then that interface plug is located behind the right-hand foot well facia (pull the cardboard under glovebox and plastic panel on the far right). It is a white, five pin, male plug. Actually, there are only three pins in the plug and it is connected to a female with only one pin. This plug exits the main ECU harness relatively near the ECU itself.

Thanks. I did find the plug eventually. I'd not thought to take off the "plastic panel on the far right", and when I did, there it was. I was at an independent Land Rover specialist's shop, and he had some sort of old handheld device with a myriad of plugs for different Land Rovers. OK I believe it said "Autodiagnos" at the top, so it was likely the Autodiagnos MT Pro as it looked much like the one at http://www.vdo.com/passenger-cars/vehicle-diagnostics/autodiagnos-mt-pro-mt-pro-ii/.

He did have a connector for the Autodiagnos that fit that plug but he couldn't get his computer to power on and read the ECU. He said the pinouts on his connector were configurable and maybe needed to be changed, but we'd run out of time at this point. 5 hours of driving and no love.

Maybe I was confused, because I thought this was the connector to reset the SRS light as well. That was really my main goal for the trip.

 

[AndrewClarke]

Upon a small amount of further research, I think this is what he has: http://www.diagnosticsolutions.ie/iopen24/pub/MT Coverage/Landrover.pdf

 

[cosmic88]

Maybe I was confused, because I thought this was the connector to reset the SRS light as well. That was really my main goal for the trip.

SRS info https://discoweb.org/forums/showthread.php?t=51379

The engine ECU is just that, engine data only. Free shareware out there and a simple homemade serial / usb plug is all you need. I think Charles Galpin still makes the interface plugs... like $30 ish.

check this out if you are so inclined... https://discoweb.org/forums/showthread.php?t=79207

 

[Jagfixer]

I think you will find that if a vehicle is over or near the 10yr. mark, the dealer's don't like touching it. Like carbs, the young techs hardly know what they are.

 

[AndrewClarke]

Thanks for the links. I'd read that thread about the SRS the other day and half forgot and half haven't had time to try that proposed SRS reset procedure with the battery and key. It's definitely worth trying first before swapping out SRS ECUs.

I also discovered that 14CUX open source application last night and spent a bunch of time reading about it. I was contemplating different connectors to use to build a cable, but ideally would keep the standard connector as I have two 1995 Discoveries I'd like to eventually have on the road. The other one's got a 1997 drive by wire 300tdi in it so who knows what the computer thinks is going on with that.

I was prepared to try to find a connector from a local wrecker with a 1995 Discovery on the lot, but I'd pay to have someone else make the cable for me, as then I'd actually have it rather than just thinking about it. I'll PM cgalpin elsewhere and nicely ask him.

At some point I need to get the radio code too, so I hope some dealer out there will help me with that at least. Otherwise fortunately there are other options.

 

[AndrewClarke]

I tried the idea from https://discoweb.org/forums/showpost.php?p=577813&postcount=4

disconnect the positive and negative battery terminals. disconnect the srs under steering column. let sit for like 10 minutes. reconnect all; turn key to second position; let sit for 10 minutes. turn engine on and run for like 10 min. if this doesnt work then drive it off a cliff.

Unfortunately it didn't work for me. So I can deduce that either:

- The procedure is bogus,

- I have a hard fault, or

- My daytime running lights for the 10 minutes of "key in position 2" wore down my battery sufficiently that the error was triggered upon restarting. I don't think it was this though as I thought to hook up a charger for most of those ten minutes.

It was worth a try, but that's my feedback, for posterity.

 

[Buddy]

Thanks for the links. I'd read that thread about the SRS the other day and half forgot and half haven't had time to try that proposed SRS reset procedure with the battery and key. It's definitely worth trying first before swapping out SRS ECUs.

I also discovered that 14CUX open source application last night and spent a bunch of time reading about it. I was contemplating different connectors to use to build a cable, but ideally would keep the standard connector as I have two 1995 Discoveries I'd like to eventually have on the road. The other one's got a 1997 drive by wire 300tdi in it so who knows what the computer thinks is going on with that.

I was prepared to try to find a connector from a local wrecker with a 1995 Discovery on the lot, but I'd pay to have someone else make the cable for me, as then I'd actually have it rather than just thinking about it. I'll PM cgalpin elsewhere and nicely ask him.

At some point I need to get the radio code too, so I hope some dealer out there will help me with that at least. Otherwise fortunately there are other options.

I had similar issues with my '95. When I got it the previous owner had put a piece of electrical tape over the SRS light. I didn't really like that so I took the gauge cluster out and removed the bulb. I also unplugged all the air bags. For what I use the truck for I would hate one to blow. Plus who knows how well a 20+ year old air bag would work.

For the serial cable I ended up making one using the single wire reset plug attached to the harness. I cut it off and then found a similar 3 pin plug and used 2 pins out of that for the two missing pins. I got the USB cable from Amazon and the whole thing worked well. Getting the right resistor is probably the hardest part. I ended up with a pack of 100 of them.