P38A Strange no-start issue, immobiliser related?

domlinson said:

Hi all,

I've got a 2000 P38 4.0 HSE Auto.

I've looked at plenty of threads on this forum regarding immobiliser issues, but I don't think my symptoms seem the same.

Here are the symptoms that my P38 has:
Upon unlocking the car and trying to start, there's about a 50% chance that the car will just crank indefinitely with no-start. The engine is actually cranking over. If this happens, I lock the vehicle with the fob, unlock it again, and then it immediately fires up when I try to start it again.

I checked OBD2 codes with a cheap scanner and I can see a P1667 which I believe is immobiliser related... This made me go down the rabbit hole of thinking that this is an immobiliser issue.

However, I've recently learnt that if my BECM was 'immobilised', the engine should not crank and I should receive a message on the dash...

So at this point, I'm a little confused.

These are the 2 theories that I have:

1. Someone has already done a partial immobiliser bypass on this vehicle, which is why it cranks even if the BECM and ECU have lost immobiliser sync.... Locking and Unlocking the vehicle just gives the BECM and ECU a chance to sync again?

2. The P1667 code is a red herring and the issue isn't immobiliser related... But i'm not sure why locking and unlocking the vehicle would enable the vehicle to start.

Neither of these theories seem particularly strong to me, so I haven't started ordering parts yet...

Anyone have any thoughts?

Thanks.

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domlinson said:

Hi all,

I've got a 2000 P38 4.0 HSE Auto.

I've looked at plenty of threads on this forum regarding immobiliser issues, but I don't think my symptoms seem the same.

Here are the symptoms that my P38 has:
Upon unlocking the car and trying to start, there's about a 50% chance that the car will just crank indefinitely with no-start. The engine is actually cranking over. If this happens, I lock the vehicle with the fob, unlock it again, and then it immediately fires up when I try to start it again.

I checked OBD2 codes with a cheap scanner and I can see a P1667 which I believe is immobiliser related... This made me go down the rabbit hole of thinking that this is an immobiliser issue.

However, I've recently learnt that if my BECM was 'immobilised', the engine should not crank and I should receive a message on the dash...

So at this point, I'm a little confused.

These are the 2 theories that I have:

1. Someone has already done a partial immobiliser bypass on this vehicle, which is why it cranks even if the BECM and ECU have lost immobiliser sync.... Locking and Unlocking the vehicle just gives the BECM and ECU a chance to sync again?

2. The P1667 code is a red herring and the issue isn't immobiliser related... But i'm not sure why locking and unlocking the vehicle would enable the vehicle to start.

Neither of these theories seem particularly strong to me, so I haven't started ordering parts yet...

Anyone have any thoughts?

Thanks.

Click to expand...

Grrrrrr said:

If the EMS and BECM lose sync it will crank but not start. I am not sure I would trust anything from and OBD2 reader though. I guess it could be RF interference but I would get a Nanocom or proper diag on it if you can.

Glow plugs are my other thought. Try cycling the ignition a few times before trying to start to get the glows really hot.

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DanClarke said:

4 Litre HSE No Glow-Plugs @Grrrrrr

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kermit_rr said:

That code has come up a few times on here, worth doing a search.
Are you sure the engine battery is good?

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DanClarke said:

You need proper diagnostics on a Range Rover. OBD2 won't cut it.
What's the battery like Volts-wise?
Where in Essex are you?

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DanClarke said:

This from another forum.

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Grrrrrr said:

Oh yeah, I was on the doozle.

Ah well, I think the later Thor will crank but the GEMS won't so it could still be RF.

I am unsure how the petrol lift pump runs. If weak and it primes only at the first turn of the key then still might be worth trying cycling the ignition before starting, or test if lift pump is delivering expected amount.

I've never had a chance to play with a Thor. Too new and shiny for me.

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domlinson said:

Thanks all for your prompt and useful replies, this forum is excellent.



I did search both for the specific P1667 code and for general 'no start' or 'immobiliser' issues, but most threads end with people recommending a re-sync (with a SyncMate for example)... However, as my issue is intermittent I wasn't sure how a re-sync would fix the issue long term, as sometimes the sync is clearly working.

Engine battery is good, it's a recent battery and after sitting overnight it was at 12V, 14.6V when engine running.



Yeah I'm learning about the diagnostics now, considering RSW EASUnlock V4 which seems to be able to interrogate BECM and other systems... It's considerably cheaper than a Nanocom, although I know it is more limited.
Battery is at 12v after sitting all night, 14.6 when engine running.
Not far from Colchester in Essex.



I found that last night, wasn't 100% sure what the resolution to the problem was but as I believe my battery is good I don't think I need to replace it. As for the poster that said it was a non-operational keyfob, I guess that's possible... I've got 2 fobs and both exhibit the same behaviour.



Interesting to know that a Thor will crank even if there's an RF/Immobiliser thing going on.
I haven't considered anything 'physical' like a fueling issue at this point, mainly because sometimes you can walk up to it after letting it sit all night and it'll fire right on the button... this makes me think the fuel pump and priming was working correctly (at least some of the time).

Click to expand...

domlinson said:

Thanks all for your prompt and useful replies, this forum is excellent.



I did search both for the specific P1667 code and for general 'no start' or 'immobiliser' issues, but most threads end with people recommending a re-sync (with a SyncMate for example)... However, as my issue is intermittent I wasn't sure how a re-sync would fix the issue long term, as sometimes the sync is clearly working.

Engine battery is good, it's a recent battery and after sitting overnight it was at 12V, 14.6V when engine running.



Yeah I'm learning about the diagnostics now, considering RSW EASUnlock V4 which seems to be able to interrogate BECM and other systems... It's considerably cheaper than a Nanocom, although I know it is more limited.
Battery is at 12v after sitting all night, 14.6 when engine running.
Not far from Colchester in Essex.



I found that last night, wasn't 100% sure what the resolution to the problem was but as I believe my battery is good I don't think I need to replace it. As for the poster that said it was a non-operational keyfob, I guess that's possible... I've got 2 fobs and both exhibit the same behaviour.



Interesting to know that a Thor will crank even if there's an RF/Immobiliser thing going on.
I haven't considered anything 'physical' like a fueling issue at this point, mainly because sometimes you can walk up to it after letting it sit all night and it'll fire right on the button... this makes me think the fuel pump and priming was working correctly (at least some of the time).

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Grrrrrr said:

I think you'll find EASunlock only does the air suspension but check Storey Wilson's website.

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kermit_rr said:

When you say 12v overnight, do you mean 12.0? Or 12.5?

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domlinson said:

12.0
Is that on the low side?

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DanClarke said:

Yes. 12.7 is GOOD, 12.4 is Passable <12.4 is likely to be problematic.
I have a Nanocom for the THOR engine P38.
You can come over here and we can take a look at settings etc. if you want. It's just your petrol costs and time.
No guarantees we can resolve anything because we don't know about your BeCM status (Locked/Unlocked) etc. But it is a start and saves you the immediate outlay for a Nanocom.

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domlinson said:

Oh interesting! As it cranks over so happily I assumed that 12.0 was OK. I'm learning that the P38 is a sensitive beast.
RE the Nanocom - That's a really generous offer, thank you! OK to PM you to arrange a time?

Thanks again.

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marjon said:

1 year they cranked another they didnt.
Squirting of fuel or fuel pump they changed. Cant remember details.

As you have a 2001 it should also sync with key in, Nothing wrong with RF if it opens on the fob?

Have you changed the batteries in the fob?

J

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domlinson said:

Ok makes sense as to why mine cranks then.
I haven't tried anything yet, I figured that if the fobs unlock the vehicle remotely then their batteries are probably OK.

Interesting that a couple of posts have referenced by engine battery now, I will see if I can test with a more accurate meter as the battery is only a month or so old so it should be more than 12.0V.

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DanClarke said:

Mine is a MY 2000 4.6 Thor engined Vogue spec. If I lose keyfob synch I get no cranking and "Engine Disabled" message on the message centre.

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domlinson said:

Thanks all for your prompt and useful replies, this forum is excellent.



I did search both for the specific P1667 code and for general 'no start' or 'immobiliser' issues, but most threads end with people recommending a re-sync (with a SyncMate for example)... However, as my issue is intermittent I wasn't sure how a re-sync would fix the issue long term, as sometimes the sync is clearly working.

Engine battery is good, it's a recent battery and after sitting overnight it was at 12V, 14.6V when engine running.



Yeah I'm learning about the diagnostics now, considering RSW EASUnlock V4 which seems to be able to interrogate BECM and other systems... It's considerably cheaper than a Nanocom, although I know it is more limited.
Battery is at 12v after sitting all night, 14.6 when engine running.
Not far from Colchester in Essex.



I found that last night, wasn't 100% sure what the resolution to the problem was but as I believe my battery is good I don't think I need to replace it. As for the poster that said it was a non-operational keyfob, I guess that's possible... I've got 2 fobs and both exhibit the same behaviour.



Interesting to know that a Thor will crank even if there's an RF/Immobiliser thing going on.
I haven't considered anything 'physical' like a fueling issue at this point, mainly because sometimes you can walk up to it after letting it sit all night and it'll fire right on the button... this makes me think the fuel pump and priming was working correctly (at least some of the time).

Click to expand...