Our '94 Disco 300 TDi Auto "Failed to proceed" the other day. Parked it. Moved it and stopped the engine again. Tried to start the engine, just a click from a relay over on the passenger side. It has done this a couple of times before, but then started after a short period of cursing and poking about under the dash. Not this time! Eventually called out the AA. He had a good go, but in the end all he could do was flick the Lucar connector off the solenoid and short across to start it so we could get home. Noticed no reversing lights, or, curiously, speedo. I can start the thing by supplying an earth to the starter relay, but this takes the inhibitor switch out of the equation, and the speedo still doesn't work. I've checked the inhibitor switch, the alarm circuit board for dry joints and continuity between the starter relay and the inhibitor switch. There is no continuity between the starter relay earth and the inhibitor switch. The only thing I can find in the line is the diode. I suspect this little beast. Does anyone know anything about the starter relay diode? Does anyone have any better suggestions? I need to fix this before the Present Mrs S trades the Disco in for some Jap heap!
94 Disco 300TDi not starting - Help!!
- Thread starter IanSig
- Start date
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discomania
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Its the security thing under the dash board, in there there is a thing with 8 wires going into it, on one side one of those wires evetully ends up going to your starter, deck a volt meter, and try each one in turn while trying to start the engine (when the fault is in place) and you will find one thats dead, simply take this dead one, cut it off and solder it to another one.
I had this problem and it was basicly a relay type thing under the dash thats controlled by the keyfob it stops your car being started if its not been disengaged, the immoboliser.
So, by earthing the starter your basicly bypassing this...
I had this problem and it was basicly a relay type thing under the dash thats controlled by the keyfob it stops your car being started if its not been disengaged, the immoboliser.
So, by earthing the starter your basicly bypassing this...
Thanks for that idea. I think you mean the transformer in the corner of the circuit board.
I've cracked it! Before I got into major surgery on the alarm circuit board, I tried a different tack on tracing the wiring from the starter relay to the alarm unit. If I shorted across the relay socket from the connection with the white/red wire to the black/orange wire, I would put 12 volts onto the wire that leads to the alarm, just as it would if you had the relay plugged in, when you turn the key to the Start position. So the result was no 12 volts on either of the black/orange wires going into the alarm. ( I took this approach after discovering that my suspicions about the diode were unfounded because it was my cheap multimeter leading me astray!) Traced the black/orange wire which turns to black/yellow after the diode through the loom across the car to the passenger footwell where it goes out into the engine compartment. Behind the screenwash bottle there is a multi-connector. The wires to and from the inhibitor switch pass through it. Unplugged it, metered across the black/green and black/yellow wire pins (they are next to each other) they are the two sides of the inhibitor switch, so no need to crawl underneath another time. Put it back together, and the engine starts. And, the speedo works, so that must go through that plug as well. Tricky little devil to get at if you don't want to take screenwash bottle out (I didn't), but it will come out to take apart if you gently persuade it.
And the Disco is back at the top of Mrs S's Christmas card list!
I've cracked it! Before I got into major surgery on the alarm circuit board, I tried a different tack on tracing the wiring from the starter relay to the alarm unit. If I shorted across the relay socket from the connection with the white/red wire to the black/orange wire, I would put 12 volts onto the wire that leads to the alarm, just as it would if you had the relay plugged in, when you turn the key to the Start position. So the result was no 12 volts on either of the black/orange wires going into the alarm. ( I took this approach after discovering that my suspicions about the diode were unfounded because it was my cheap multimeter leading me astray!) Traced the black/orange wire which turns to black/yellow after the diode through the loom across the car to the passenger footwell where it goes out into the engine compartment. Behind the screenwash bottle there is a multi-connector. The wires to and from the inhibitor switch pass through it. Unplugged it, metered across the black/green and black/yellow wire pins (they are next to each other) they are the two sides of the inhibitor switch, so no need to crawl underneath another time. Put it back together, and the engine starts. And, the speedo works, so that must go through that plug as well. Tricky little devil to get at if you don't want to take screenwash bottle out (I didn't), but it will come out to take apart if you gently persuade it.
And the Disco is back at the top of Mrs S's Christmas card list!
discomania
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Glad it worked out, not sure which part you mean with the transformer, this thing looks almost like an ECU, except with only 8 wires, its situated under the central dash area, bloody stupid place to put it.
LR GUY
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not so stupid when someones tryin to nick your motor!!!!!!! i take it your on about the immobilisation unit behind the dash, if this fails you can get a new kit from land rover where you have a new tag to wave over the column before you start the car think there about 80 quid
I think the Immobiliser that's in the middle of the dash is known as a Spider, and it was fitted from '96 on. Which is why, Discomania, I seem to have been talking gibberish! My '94 model has the immobiliser built into the alarm unit which is tucked away in the dash on the passenger side, and has a transformer with 8 connections. I believe the Spider has something of a reputation, not all of it good!
Hi,
Mine discovery seems to be having the same problems as yours (will start once but once stopped in the cold usually, it won't start again for an hour or so.).
I've removed some of the dash/central console and found there is not black box!!! Does your discovery (L reg/1994) have the radio which slides down at a 45 deg angle in the centre and the heating controls are on stalks. If so, where did you find the problem? I have found the central locking unit which is located under the drivers footwell but I'm still not sure if that is the problem? Any idea's????
Mine discovery seems to be having the same problems as yours (will start once but once stopped in the cold usually, it won't start again for an hour or so.).
I've removed some of the dash/central console and found there is not black box!!! Does your discovery (L reg/1994) have the radio which slides down at a 45 deg angle in the centre and the heating controls are on stalks. If so, where did you find the problem? I have found the central locking unit which is located under the drivers footwell but I'm still not sure if that is the problem? Any idea's????
Hi. My Disco is a '94 M reg. The radio goes in horizontally at the top of the centre panel.
Perhaps I didn't make my solution clear in my 'fixed it' posting. The problem was the multi-way connector behind the screenwash bottle. It had either worked a bit loose or had a bit of corrosion on the pins.
Since then the old girl has always started. So I think 18 months is probably long enough to call that a fix!
The connector is tucked away between the screenwash bottle and the bulkhead. As I said before, the easiest way would be to remove the bottle, but I am blessed with skinny fingers and managed to ease it out without taking bottle out.
I think if the immobiliser is the problem then the location of it depends on the year it was made. Which is not a bad thing, a moving target is harder to hit!
Hope this helps.
Perhaps I didn't make my solution clear in my 'fixed it' posting. The problem was the multi-way connector behind the screenwash bottle. It had either worked a bit loose or had a bit of corrosion on the pins.
Since then the old girl has always started. So I think 18 months is probably long enough to call that a fix!
The connector is tucked away between the screenwash bottle and the bulkhead. As I said before, the easiest way would be to remove the bottle, but I am blessed with skinny fingers and managed to ease it out without taking bottle out.
I think if the immobiliser is the problem then the location of it depends on the year it was made. Which is not a bad thing, a moving target is harder to hit!
Hope this helps.
Discophil34
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Hi IanSig ,i realise this post is really old but your fix fixed mine by reconnecting the diode doofer behind the screen wash reservoir. But my question is why? It didn't make sense , but thought it worth a try . And it worked . The story is I had a starting issue following jet washing my disco. It started fine after washing ( severe washing with jet wash) apart from wouldn't lock with remote, it would try then immediately unlock, then nothing. Got home and got kids for school went out to start it , nothing, immibiliser light came on , no start, and no remote locking.
why would this be solved by reconnecting the diode doofer that has been disconnected for over a year as I don't particularly like the dull dipped beam thing as I have led side lights and think it looks strange?
why would this be solved by reconnecting the diode doofer that has been disconnected for over a year as I don't particularly like the dull dipped beam thing as I have led side lights and think it looks strange?
discool
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Why bother, he hasn't been around since December 2007, and what are u talking about? Diode or Resistor.
Discophil34
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Discool , it's the resistor for dimming the lights when on side lights , according to the original post (who called it the diode) by reconnecting this it solved starting issue as it DoD mine , I'm just looking for an explanation as too why? I realise all to much that this is an exercise in futility with land rovers sometimes but none the less , I like to know WHY things work, not that they just do.
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