Disco 2 Auto Disco II cranks but will not start 3 Amigo's + M&S flashing!

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Neptune19522 said:
The main relay, R9, comes on but the other two, fuel and engine, R6 and R1, do not engage
Click to expand...
That's the gist of it, aamof R6 is not "engine" but glow plugs though the fact that R1 does not kick in is the main issue, measure voltage across the parallel cavities of R1 in the fusebox when you turn ignition on, R9 should send the positive feed to the coil and the ECU the earth on pin 5 of the black plug(C0658), investigate on that path to make sure it's not an interruption in the fusebox.... as R9 kicks in but R1 and R6 doesnt te ECU becomes suspect too
Neptune19522 said:
It could be the battery; it is not unknown but it is vary rare.
Click to expand...
It's not rare at all but based on what you revealed about R9 and R1 seems ruled out even though if the voltage drops hard while cranking the ECU can have an odd behaviour
MJI said:
Immobilser triggered?
Click to expand...
the immobiliser doesnt let it crank and R9 would not kick in as well
 
The spectacle of a failed ECU is always present! If you get one off E-bay then is it usable and if it is and it proves the original one was usable then a very expensive test. Do you know of anyone who could test an ECU or replace one? Then again I will need some form of reprogramming equipment to make it fit into the extant vehicle system. It's a minefield of expensive tests and ramifications.

Given that the M&S lights have been coming on on and off for about a year would some testing of the EAT and surrounding harnesses be beneficial?
 
sierrafery said:
That's the gist of it, aamof R6 is not "engine" but glow plugs though the fact that R1 does not kick in is the main issue, measure voltage across the parallel cavities of R1 in the fusebox when you turn ignition on, R9 should send the positive feed to the coil and the ECU the earth on pin 5 of the black plug(C0658), investigate on that path to make sure it's not an interruption in the fusebox.... as R9 kicks in but R1 and R6 doesnt te ECU becomes suspect too
It's not rare at all but based on what you revealed about R9 and R1 seems ruled out even though if the voltage drops hard while cranking the ECU can have an odd behaviour
the immobiliser doesnt let it crank and R9 would not kick in as well
Click to expand...

But that is what mine does, cranks fast no firing.
 
Watched a long Youtube last night from Dan the Diagnostic man.
Cranked but wouldn't start, AND there was a wave from the crank sensor.
Turned out the "fresh out of the box" Bosch crank sensor had been wired wrong!
He tried a cheapo ERA (or something) crank sensor and all was solved.
The wave form on the oscilloscope showed the wave was inverted.
So he took the wires from the Bosch crank sensor and swopped them. THEN the Bosch one worked.
Just saying!
 
MJI said:
But that is what mine does, cranks fast no firing.
Click to expand...
And all i said is that the immobiliser doesnt let it crank so as long as it cranks it's not immobilised: from the WSM :
"...
Once the ignition is switched on, the BCU transmits a coded signal to the ECM. If the coded signal does not
correspond to the programmed code in the ECM, the ECM is inhibited and the BCU inhibits the starting circuit..."
 
sierrafery said:
And all i said is that the immobiliser doesnt let it crank so as long as it cranks it's not immobilised: from the WSM :
"...
Once the ignition is switched on, the BCU transmits a coded signal to the ECM. If the coded signal does not
correspond to the programmed code in the ECM, the ECM is inhibited and the BCU inhibits the starting circuit..."
Click to expand...
I don't know what this issue is but it cranks fast, after a hiccup.

I remove key open door close door, lock, unlock, open, close, starts up when I try again
 
Sierraferys, in response to your request:- R1 and R6 coil voltage, across pins 85 and 86, both show 0V on cranking! Battery volts on cranking:- 10.95V. This is pointing the finger directly at the ECU I am thinking? Anyone got a good ECU I could use to prove this point?

Now the air suspension is working by pulsing the AirSus pump. (Got the front wheels well of the garage floor, and chassis on stands, so I could get to the xyz switch)

I did the electrical mod to remove one of the Amigos about six months ago; not sure if this is the ABS complaint or not.

Sierrafery, your page stats that you can test ECUs, if you are not too far from me, here in Warwick, could I drive to you, (in my very old 88" so not to far), and perhaps you could test the engine and transmission ECU's? I did try to remove the cover from the engine ECU but only succeeded in shearing one bolt and removing the other three. All were very rusty, more than you would expect from a 19year old vehicle. Not a promising sign for the ECU's performance...
 
MJI said:
I don't know what this issue is but it cranks fast, after a hiccup.

I remove key open door close door, lock, unlock, open, close, starts up when I try again
Click to expand...
Exactly what mine does, once or twice a year. Exactly what I do also! This bit from the WSM, 18-1-38, seems to explain it, so the WSM seems to contradict itself:
"...
Immobilisation system
When the starter switch is turned on, the BCU sends a unique security code to the ECM. The ECM must accept this
code before it will allow the engine to operate. If the ECM receives no security code or the ECM receives the incorrect
security code, then the ECM allows the engine to run for 0.5 seconds only. During this operation all other ECM
functions remain as normal."
 
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Neptune19522 said:
Sierraferys, in response to your request:- R1 and R6 coil voltage, across pins 85 and 86, both show 0V on cranking! Battery volts on cranking:- 10.95V. This is pointing the finger directly at the ECU I am thinking? Anyone got a good ECU I could use to prove this point?

Now the air suspension is working by pulsing the AirSus pump. (Got the front wheels well of the garage floor, and chassis on stands, so I could get to the xyz switch)

I did the electrical mod to remove one of the Amigos about six months ago; not sure if this is the ABS complaint or not.

Sierrafery, your page stats that you can test ECUs, if you are not too far from me, here in Warwick, could I drive to you, (in my very old 88" so not to far), and perhaps you could test the engine and transmission ECU's? I did try to remove the cover from the engine ECU but only succeeded in shearing one bolt and removing the other three. All were very rusty, more than you would expect from a 19year old vehicle. Not a promising sign for the ECU's performance...
Click to expand...
Oops!
Doubt your 88" would make it to Transylvania!:eek:;)
 
Neptune19522 said:
Sierrafery, your page stats that you can test ECUs, if you are not too far from me
Click to expand...
Unfortunately i'm very far from you, in Romania:cool:
Neptune19522 said:
R1 and R6 coil voltage, across pins 85 and 86, both show 0V
Click to expand...
you have to put one probe to an earth(body) and the other in pin 85( check in 86 too to be sure) and see if you gt 12V to make sure that the earth from the ECU is missing and even if it is you have to check the output from the ECU C0658-5, if you dont get 12V against earth in any of the coil cavities the problem is within the fusebox cos the positive feed is delivered by R9.... seems that you know to read a diagram so download them from here(in the Electrical library you have the connector views): https://www.dropbox.com/sh/47hbz40an5he5j2/AACH509eV_o7QhM5PoX6eFVLa
Neptune19522 said:
Battery volts on cranking:- 10.95V
Click to expand...
that's a bit low for an auto, not a value which can give any certainity... that 10.5v i said is lower limit, below 11V nothing is certain and the multimeter's accuracy is a factor too, the gist is that the ECU needs solid 12V to work well, especially the EAT ECU.
 
I worked for Land Rover for 43 years the last severn were spent drawing the circuit diagrams, which software converted into harness drawings, these are the drawings you have indicated; I worked almost exclusively on Defender! Prior to EDS department I worked on System Test where we ensured that above the tests that each engineer carried out on his, or her, component we tested all components together. Three of those tests was that all ECUs would cope with reverse voltage, with the so called lorry start where 24V was the supply voltage and that all electronic components would continue to work at 9V i.e. when the battery voltage was pulled down by the starter motor running. I measured 10.95V at the battery terminals of my 19 year old Discovery II; it therefore passes all of the tests that Land Rovers were required to pass before sale to the public. If it was / is good enough for Land Rover I think I am happy that there is adequate voltage to pull in the two relays on my Discovery II 'if' the ECU provided the negative side as it is designed to do. Mine does not therefore it is probably deficient assuming all other factors are correct; which the past two days has proved that they are. In my position of testing Land Rovers for the company I would pass this installation that I have but I would condemn the ECU which I have.

I am hoping to contact the engineer responsible for the design of the TD5 ECU direct and again hoping that he can advise me on the best way of progressing. This is a well that can only be visited once!

I thank you and other members for the assistance I have received while pursuing this fault on my 19 year old vehicle, at Land Rover I only worked on prototype vehicles that do not have the test of time which this thread does have, however I will hold to the standards that I worked to whilst employed by Land Rover.
 
Neptune19522 said:
I worked for Land Rover for 43 years the last severn were spent drawing the circuit diagrams, which software converted into harness drawings, these are the drawings you have indicated; I worked almost exclusively on Defender! Prior to EDS department I worked on System Test where we ensured that above the tests that each engineer carried out on his, or her, component we tested all components together. Three of those tests was that all ECUs would cope with reverse voltage, with the so called lorry start where 24V was the supply voltage and that all electronic components would continue to work at 9V i.e. when the battery voltage was pulled down by the starter motor running. I measured 10.95V at the battery terminals of my 19 year old Discovery II; it therefore passes all of the tests that Land Rovers were required to pass before sale to the public. If it was / is good enough for Land Rover I think I am happy that there is adequate voltage to pull in the two relays on my Discovery II 'if' the ECU provided the negative side as it is designed to do. Mine does not therefore it is probably deficient assuming all other factors are correct; which the past two days has proved that they are. In my position of testing Land Rovers for the company I would pass this installation that I have but I would condemn the ECU which I have.

I am hoping to contact the engineer responsible for the design of the TD5 ECU direct and again hoping that he can advise me on the best way of progressing. This is a well that can only be visited once!

I thank you and other members for the assistance I have received while pursuing this fault on my 19 year old vehicle, at Land Rover I only worked on prototype vehicles that do not have the test of time which this thread does have, however I will hold to the standards that I worked to whilst employed by Land Rover.
Click to expand...
In view of all the above it would seem that you are one of the best qualified people on the planet to diagnose faults in the connections, loads etc TO the ECU. And under what conditions we could expect a NEW LR to work.
But as you have said, your TD5 is 19 yrs old. As is probably the ECU.
So I am looking forward with baited breath to you getting your erstwhile colleague to provide you with circuit diagrams, testing procedures etc for what goes on inside the ECU so we can all learn from it and repair our own ECUs.
I for one have a bust one that an electronic engineer could see no physical fault with, which she was looking for, with her microscope, as "all" I did to it was drop it once it was disconnected from the car.
I hope he/she isn't bound by the Official Secrets Act.
At the time all I could do was get a secondhand one from the internet, connect it then get a garage to get the ECU to "talk to" the BCU, which then enabled it to run. Although he did put the injector codes in too.

Really following this thread intently.
And this is no slur on @sierrafery or anyone else on here who DOES know what goes on inside the box of tricks. I am just in the stone age when it comes to electronics.
 
Neptune19522 said:
I worked for Land Rover for 43 years the last severn were spent drawing the circuit diagrams, which software converted into harness drawings, these are the drawings you have indicated; I worked almost exclusively on Defender! Prior to EDS department I worked on System Test where we ensured that above the tests that each engineer carried out on his, or her, component we tested all components together. Three of those tests was that all ECUs would cope with reverse voltage, with the so called lorry start where 24V was the supply voltage and that all electronic components would continue to work at 9V i.e. when the battery voltage was pulled down by the starter motor running. I measured 10.95V at the battery terminals of my 19 year old Discovery II; it therefore passes all of the tests that Land Rovers were required to pass before sale to the public. If it was / is good enough for Land Rover I think I am happy that there is adequate voltage to pull in the two relays on my Discovery II 'if' the ECU provided the negative side as it is designed to do. Mine does not therefore it is probably deficient assuming all other factors are correct; which the past two days has proved that they are. In my position of testing Land Rovers for the company I would pass this installation that I have but I would condemn the ECU which I have.

I am hoping to contact the engineer responsible for the design of the TD5 ECU direct and again hoping that he can advise me on the best way of progressing. This is a well that can only be visited once!

I thank you and other members for the assistance I have received while pursuing this fault on my 19 year old vehicle, at Land Rover I only worked on prototype vehicles that do not have the test of time which this thread does have, however I will hold to the standards that I worked to whilst employed by Land Rover.
Click to expand...
Before you condemn the ECM to the dustbin, it may be worth doing a simple continuity check between R1 pin 86 in the fuse box and C0658 pin 5, the ECM connector. And just one final thought, if the only thing wrong with the ECM is it cannot switch R1, you could link 30 and 87 of R1, which will run the pump, and see if it will start.

And +1 with what you said above.
 
Like you Stanleystreamer I have no idea what goes on inside those magic boxes but I can read a specification list. My job in the closing years of my employment was to supply each box with what the engineer specified. For this knowledge of circuits was an advantage as once I found a drawing that had a direct link from battery to chassis with no fuse! However what went on inside those boxes was of little import to me as long as the engineer responsible approved of the circuit before it was published. Of course I had a smattering of electronic knowledge, (the milli-amp gang), but I majored in electrical work, (the maxi-map gang). Definition of an electronic engineer:- one amp is a lot of current and one second is an eternity! Electrical engineer;- one second is almost not worth mentioning and 10 amps is just about enough to start with. Hence I know what voltage an ECU should be able to tolerate but how they do that is a black art. I now need to find out what goes on inside some particular box; the engine ECU and perhaps the EAT of my Disco2.
 
PopPops,
Thank you for that heads up. R6 has a resistance of 103.6ohms while R9 and R1 has a resistance of 1.4ohms and 1.2ohms respectively. The high readout of R6 is probably a variable temperature switch otherwise the glow plugs would operate at all times and not when they are needed. Therefore the ECU has an opportunity to switch on R1 but does not. This alone is no reason to fail the unit as currently I have no way of checking that the other ECU's are not stopping the engine. Both the EAT and ABS units may have a veto go engine running if they detect a problem. But that is the black art...
 
Neptune19522 said:
PopPops,
Thank you for that heads up. R6 has a resistance of 103.6ohms while R9 and R1 has a resistance of 1.4ohms and 1.2ohms respectively. The high readout of R6 is probably a variable temperature switch otherwise the glow plugs would operate at all times and not when they are needed. Therefore the ECU has an opportunity to switch on R1 but does not. This alone is no reason to fail the unit as currently I have no way of checking that the other ECU's are not stopping the engine. Both the EAT and ABS units may have a veto go engine running if they detect a problem. But that is the black art...
Click to expand...
If the resistance of the "cable" between R6 pin 86 and C0158 pin 29 really is 103 Ohms, that will need investigating at some point as it should be more like the other 2, but the TD5 doesn't NEED glowplugs to start until it gets seriously cold.

Neither the EAT nor ABS ECUs can inhibit starting. In addition to your other investigations of the design of the TD5 ECU, I think you need to connect dedicated diagnostics to talk to the ECM.

Good luck, don't get downhearted.
 
Fortunately I have my 44year old series III to get about with, I was actually at Solihull when it was built and I might have even walked past it one day, but it is not the most comfortable transport for a pensioner. But then again I have no time constraints either.

Thank you for your thoughts and good whishes.
 
Neptune19522 said:
I am hoping to contact the engineer responsible for the design of the TD5 ECU direct and again hoping that he can advise me on the best way of progressing. This is a well that can only be visited once!
Click to expand...
IMO that's not the way to troubleshoot this thing... though it seems that you know better but i'm up to bet my house that you'll not find an engineer who'll tell you "secrets" about the Td5 ECU's construction or function related to your problem
if you go that way i inform you that the Td5 ECM was originally made by Lucas automotive on the "base" of a Motorolla hardware, good luck
 
Last edited:
I could connect to the ideal diagnostic bit of kit if I can fine the connection component. Has anyone out there access to a DTC0006A component or knows where I can purchase one. There appears to be a company in Germany who repair these but as the site is all in German I am unsure if the could supply one. Company name / web site, I think, is "n1m1.de"
 
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