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1995-2002 Range Rover P38A
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Discussion Starter #1
Morning, my 2001 4.6 has a weird problem

I turn the key and the red EAS lights and HEVAC lights and fan do NOT come on, all other lights normal, incl engine light
Also, the buzzing noise the ABS pressurizing (I think) makes is not there, and the slow 35 mph message comes up
Motor cranks, but won't fire, checked and there is no spark
Connect RSW software and it says cannot communicate with motronics
Checked all fuses, swopped some relays, nothing, just cranks

I disconnect the diagnostic cable and stand and look at it
Turn the key again and suddenly it is back to normal, starts and drives

Next morning, same story, but connecting and removing diagnostic cable does not fix it
Message on dash says "diagnostics" so the cable makes contact, but RSW says "Fault: cannot connect"
Battery is fully charged and I connected a charger just in case, no change

Any suggestions on where to start looking
 

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1995-2002 Range Rover P38A
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768 Posts
Thor’s will crank even if partial immobilised, I had a very similar proble
m, turned, out my becm had gone into a lockout status
 

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1995-2002 Range Rover P38A
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125 Posts
Discussion Starter #3
More info, with my limited electronics knowledge
NB my fusebox is YQE103410 NOT AMR6476 as used in the 1998 model, so I could not swop them to test
The engine cranks when I turn the key, but there is no spark so it does not start
Also, turn key to position II, ABS pump does not come on, no HEVAC power - no fans, no LCD, no working buttons, no EAS lights either

Ignition off, I removed relay#17, the ABS pump relay
Terminals - #30 has 12 volt, #86 no power, #85 earth, #87 nothing, as it should be
Shorted terminals 30 and 87 - ABS pump started, as it should
Turned key to position 2 - terminal 86 is 2.2 volt - not enough to power the relay ??
Before I take the fusebox apart, does this mean a possible bad connection in the fusebox or the supply to the fusebox
Not sure which relay to test for the HEVAC display, I suppose I can test them all

If it is a bad fusebox connection, why happen overnight, or more importantly, why did it happen to more than one relay at the same time?
Unless there is a common 12v supply that supplies power to all the relays when I turn the key
In that case it points to a problem in that wire, maybe from the ignition, but all the dash lights work, or do they bypass the relays

Is there one common wire that sends power to all the affected relays on turning the key?
I assume if I test the other relays and they also register low voltage then it is a common supply problem and not the fusebox
Am I making any sense?

William
 

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1995-2002 Range Rover P38A
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768 Posts
Mine, like yours decided it wasn’t going to play , I parked up, came back to car 10 mins later and it just cranked, I was newish to p38 electrics and problems then, I’d been lucky on having other p38s that weren’t a problem in any way, I had to send my becm off and have it sorted by people with the correct software, when I asked what had happened , I was told it had gone into a lockout status, as for what that really means, who knows !.
i would hold back on changing the fuse box, until your certain,
 

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1995-2002 Range Rover P38A
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Right,
You could have any number of electrical issues here.......
You could start by printing a copy of the electrical sticky at the top of this forum, and following it.
Pay particular attention to earth points as they can get a bit corroded and cause all kinds of gremlins.
As for fuse box, check all of the Maxi Fuses as they each provide power to a large subset of systems. RAVE will tell you just which ones. At the least, remove the fuse box, carefully pull it apart (5 screws, and clips on all sides of the case) and check internally as well as looking carefully into each of the colored plugs on the underside. Check for burning or corrosion. The 3 main cables on the bottom should also be removed, cleaned and re tightened.
 

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1995-2002 Range Rover P38A
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417 Posts
I wanted to throw this info in, when I replaced fusebox I noticed some of the wires were rubbing and could possibly wear down and touch metal.
I put some heater hose around them to protect them.
 
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