P38A all of sudden wont restart

"97 P38 4.0 Gems gas, auto, was out shopping came back and wont turn over. No clicking starter nothing.
Did all the basic checks - keys in pos II - battery disconnect
Battery good, super lock working, all the rest of radio, heater, lights, working, checked all the fuses, relays no indications burns or smell of smoke. Checked all the doors / hatch (happened once before - loose hatch)
Never tried before but shift wont move to neutral. But is in park. Turn key to start pos - display only indicate typical reoccurring things like washer fluid low, particular windows not set but nothing else. Checked door locks / communicating between all locks - lock / unlock controlled by drivers passenger. When I reconnected battery all the doors locked - had my spare key. Did have a check and service engine light on. From last time out. But with covid protocols etc was not taken to shop.- though only two shops in city have any experience But checked everything for fluids (and above ) nothing. Run it mostly in sport mode but never a stall, back fire, slip of trans nothing - battery slowly dies if not driven but understand that is typical. - the OBD reader Nano Evo is apparently $780 CA here though have to order from other countries. Suggestions.

Welcome to the mad house.
If the shifter will not move to neutral, it's quite possible that even though the lever is in the park position that the interlock switch is not activating which will give the symptoms your car has.

Sorry, super early here - mothers day and the Edmonton oilers hockey payoff run (04:10 Hrs) Rovers or P38 are so appropriately a Sherlock episode - will look up the interlok switch? But then what "drives" controls its operation? I guess i have been lucky with this one - only the second owner and five years in. I heard about the model - so as soon as I was given it - i replaced all the fuses, all relays, lights etc, rebuilt all brakes, all the passenger door lock assemblies ( a couple had failed ) new front wind screen etc. Just to remove all the minor variables. A couple things I forgot to mention earlier, when i stopped to go grocery shopping and grabbed a reusable shopping bag, I found one of the tail gate cables had broken. I took a look and removed it following - hoping it was an answer but found the mounts are isolated / ungrounded (bakelight washers and plastic washer for bolt head) so not an apparent contributor./ ground.
As i fiddled and fought with this - I noticed that progressively - when I tried to get it to start - key pos III - (sporadically) the radio went black / power went out but then when i turned the key back (position I) the radio went back on - no need to reset security code??
My mind - from other vehicles - went is it maybe an ignition harness issue - or does it exist in the same manner and contacts becoming warn?
Another item I missed earlier - prior - for some reason (sporadically) when i turn on the left signal light - it will click away and then all of a sudden double click and show an indication of a bulb failure - which is not the case - all lights and bulbs are operational??
The brake pedal switch - light switch - has already been replaced.
And something else i noticed (forgot earlier) - when I depress the brake for the "start" sequence - and turn the ignition key to III - I feel a tap / thunk back on the brake pedal a second or two after I turn the ignition key?.
I do not recollect anythiny like that before.
As i said Holmes
Thx for the help and will research the interlock
Cheers,

Sounds like a bad earth to the engine ,possibly...try moving the gear selector slowly from p ,to,1 while trying to start ,might connect ,say 2nd n start,then its a bad or mis aligned xyz switch,,,, o keep foot on brake just in case it starts....

On rangerovers.net there's an electrical troubleshooting guide. Might be worth working through that and just making sure all earth points are good.

Also check the driver's carpet is dry, assuming the BECM is under the driver's seat on what I assume is a left hooker.

Try a jump lead from the battery negative to the engine block that would confirm if the earth cable is shot.
and make sure the battery is 100%

frozen north said:

I noticed that progressively - when I tried to get it to start - key pos III - (sporadically) the radio went black / power went out but then when i turned the key back (position I) the radio went back on - no need to reset security code??

Click to expand...

Sounds like a Battery or connection issue.
When trying to start it is suppling something enough to drag battery down. When you release the key it goes back to suppling the rest of the system.
If it was something not giving "permission" to start I wouldn't think this would happen.

So as mentioned check all the earths and also give the battery a test to see its condition, clean those leads too.

J

Grrrrrr said:

On rangerovers.net there's an electrical troubleshooting guide. Might be worth working through that and just making sure all earth points are good.

Also check the driver's carpet is dry, assuming the BECM is under the driver's seat on what I assume is a left hooker.

Click to expand...

Under the passenger seat on LHD, same side as the O rings.

If the radio goes off, as others have said, a bad connection somewhere is likely. In addition to what the others have said, check the fuse box for burning smells and that the battery connection to the fuse box is tight.

Yes, drivers side is left - vehicle built Nov "96 specifically for NA. The hand inscribed "build" label is still under the "bonnet". But gas is still on right side. I have the digital version (5600 odd pages) of the owners / shop manual. Though I wish the "parts" diagrams were more like the recent style with the exploded / interacting drawings rather than the specific snap shots. I'll start mapping out electrical.& grounds. The "grounds" I have always known about and keep an eye on all those that one can see readily. This vehicle has zero rust any where - was surprised the tail gate cable was so rusted but given its right in the tail gate drain well made sense.. .
Went over / pulled / inspected all - engine area and under passenger seat. Pulled all the relays and inspected for any burn or malformation from heat. I assume for relays that is not always an indication of failure though. But I only have a couple spare relays on hand to exchange in and try .Vehicle interior is bone dry so unless barometric humidity is an issue - but wouldnt think so given what country the unit was built in. With the radio bit - didn't happen right off and appeared after trying to start it a few times - so assume something (connection / relay / some intermediate point deteriorating) progressively.
AES - I think is its own "thing" as it were - compressor has been going off a bit lately and actually dropping to "entry" level more. But I think I need to change out the rear bags - was waiting for spring to arrive here reliably to get to that one.- realistically that project will be the biggest project I've had to do on this unit.- well until now.> will go through, try and check on all of these and report back. Thx all
. .

Holy sh... elect trouble shoot - found it on the other site - i think. Quickly looking at those forums and all the current issues - dont know maybe i just want to look to the old school - less tech - models - or do they give a certificate or degree with this?
But we have pretty much zero "old school" options in western CA - what few there are are either not enough parts left in one piece or a very few that are near perfect / restored / modified @ $90 - 180K
But I caused a stir and have the "auto club" who are now sending another firm to move the vehicle to where it should be up the driveway so I dont look like an idiot working on the street.- and with the guy down the block with the tesla dont want to provide him any entertainment.
Will get back Cheers

I would measure battery voltage just to make sure that is OK. Should be at least 12.4 volts. Clean up the battery posts and cable ends once again to be sure they are OK. If all the other connections check out (loosen, wiggle, re-tighten) I think I would jump the starter to see if it still works. After that I don't know. I think a faulty XYZ switch can inhibit starting.

Being a GEMS, something to check. When you turn on the ignition, does the Check Engine Light come on? If it doesn't then the ECU and BECM have fallen out of sync and no amount of fiddling will get it going until you get them synced up again. A Syncmate or nanocom will be required. If it does, then your problem is elsewhere. I'd start at the starter motor. Take out the starter relay and jump the connections to see if it spins over. If not, there is your issue, if it does, move on to the next phase!

The ancillaries like the radio aren't connected when the engine is cranking, so will go off when you go to start.

I saw that some where - The check engine was coming on but when i did the disconnect batt / key position II reconnect batt bit. That appeared to clear some codes. But following the orange check engine isnt coming on now just get all the typical lights and red engine light.
When I did reconnected the battery all door locks auto closed properly - But had spare keys with me.
Key fob / super lock / security etc still all works.
Actually - the week before - doors would lock off the key fob but not super lock all the time and then progressively deteriorated to just locking but no super locking. Thought the fob batteries were just needing replacement.
After i did the batt disconnect / pos II bit - super lock was restored.?
But got the rover in the driveway properly today so I can now more effectively address.
I actually went through / familiarized my self with the electronic Rover II / P38 shop manual etc of 5198 pgs I got three years ago - just in case.
Have identified all the earth grounds / locations. So if it isnt raining tommorrow I'm going to set the key to position II and check through all the "systems" that are working to remove any variables and electrical paths / earth grounds that are not (apparently) effected. Printed the 20 pages of schematics - so i could better see relationships in driveway.
The Batt in its self should be fine (only 4 - 5 wks old ) but likely drawn down a bit from the initial beating my head against the wall. So will disconnect batt completely and put in on charger to bring it up to the 12.6 - 14.2 level for going forward.
Had already checked all the fuses / relays.
Looked up the syncmate / nanocom "gear" at the onset - ouch for price at least here and likely no one around here has those other than one shop possibly. Now I know someone who knows the owner so will see if I can cut some deal / favour.
If I do manage to get the sync etc "easily" it would likely be a one off / one chance thing. Maybe like a couple hours one day or a sunday when the shop is closed.
So I will remove other possibilities - as have been suggested, test starter, check grounds etc in the next day or two .
Only one other thing that would happen earlier - which I dont know if it is a contributor / clue or not - is the left turn signal would be operating properly but then every so often while sitting in left turn lane - it would start to double click and show on display that there was a bulb failure - but the bulb was fine - and then it would be fine for days./ weeks so some odd dead ground or maybe a damaged wire? One of my conventional trucks did that and I just needed to change the signal assembly an internal issue.
I'm curious as to what would make the ECU BECM to fall out of sync?
By coincidence i should be seeing the person who knows the shop owner tomorrow night.
So will work my way through in the next couple days and advise.
Thx allot for the help, cheers,

In my experience the ECU falls out of sync from RF interference, normally from something like a wireless weather station. Gen 3 reciever (£££) sorts that or Marty's filter (££) or Brian's second remote jog fob (£).

I think RF frequency is different in the Americas (315MHz) but anything on that frequency will scramble it. Some countries all had the same EKA code as well (1515). No loss in trying the EKA. Or disconnecting the battery for 30 minutes.

There was something about earths and early GEMS. It'll be in the engine bay. Is there one to the wing from the bottom of the engine that rots or something like that?

Datatek said:

Under the passenger seat on LHD, same side as the O rings.

Click to expand...

That makes sense. Why change more than you have to.

If the o-rings on the heater matrix join are good (qnd he says carpet is dry so should be) then no worries there.

A word to the wise never use superlock as when the car throws a hissy fit you will be in a whole new world of pain trying to get doors open which normally entails breaking stuff and cutting bits off.

If the Check Engine Light isn’t illuminating, then the ECU and BECM have fallen out of sync. It is nothing to do with RF filters and the like as they are hard wired together. When you turn on the key, the BECM sends a code to the ECU. If it is the code the ECU expects to see, it powers up and you can start the car. If not, it stays asleep.

in order to fix the problem you have to go in and enable the security learn feature in the ECU. That way it accept the next code it gets as being correct.

FYI disconnecting the battery in a P38 does nothing it terms of the system, it just means you have to re-set all the windows etc.

Well last night it snowed lightly / melted so is wet and only 3C today -so just went through my electronic rover shop manual.
Vehicle is secure now so some urgency over and a little nipplish to be out side messing with today
Normally realistically this roija is only driven one day a week from spring to late fall and a couple times during winter snow storms because its funny watching the rest stuck or slipping around through my heated windshield.
Have schematics in hand, located all the engine compartment grounds
So will check / confirm which or if all other systems are operating. Then check battery status now and then disconnect and put it on charger to bring the new batt up to full charge in advance.
Then first checking earth grounds and not zap my self.
Once I reconnect battery will go back with meter to double check continuity
Remove as many possibilities in advance - try to talk "buddy" into lending me his "gear" - which I assumes he has at his shop (Sync - Nova)
Or maybe pay him to come past house - dont feel like paying towing on dollies half way across town.
Grrrrr - the RF bit is bizarre to be so twitchy.
But the references Gen 3 , Martys & Brians has me lost?
Sync mate here ranges depending on supplier $400 - 1300 CA
Novacom P38 is around $800 CA plus a couple weeks to get either of them shipped.
I thought I wanted to kill my self when I replaced the correct "wind screen" for $900
Brianp... - super lock can crater that hard? - can it then ignore the drivers side key? Is this another BCEM thing? I found very good used then cleaned, greased and replaced all door locks three years ago.
And checked all adjacent wiring as I had interior door panels off.
This couldnt be that brake pedal switch thing again - all $25.00 bucks worth of it? I did replace it 5 yrs ago but cant remember the specific reason for then?
But it was cheap and relatively easy maybe just replace to be done with it again.
Still cant think of what is the bump or tap I feel a couple seconds after when I depress the brake to turn key ignition - dont recollect that happening before.
Thx for all the help - I guess I have been fortunate with this unit but it did have an easy / gentle life.