I assume the bonnet switch is attached to one of the catches on the slam panel. I’ve had the slam panel off many times but never had to disconnect any electrical wires (or noticed any dangling about under it)! As for the EAS operating, I’ve never noticed but, then again haven’t had the bonnet open and the vehicle locked on many occasions (or driven it with the bonnet open)!

Yes, bonnet was closed with ammeter on top of bonnet. However, bonnet open or closed doesn't make any difference and there is no 'open bonnet' warning ever displayed and the car will lock quite happily and set the alarm with the bonnet open and no 'chirp' from the alarm sounder as it will for any of the doors. It's always been like this since I have had it!

When the interior lights go out the current draw drops from over 3A and then ‘wangs’ about at various values between 1.6A & 2A. If it was a flashing light or similar I would expect it to jump up and down consistently between two values but it doesn’t, it seems to be all over the place. When all this stops at the 2 minute mark the 570mA holds rock steady for the final minute or so before it finally drops to the 35mA. It’s not the alarm LED.

It’s strange to be sure and I can’t think what circuit would be ‘live’ for two minutes with a varying current. I assume the steady 570mA is the BeCM and the actual ‘wanging’ about is something varying between ~1A and ~1.4A on top but I can’t think of anything that would do this and then shut off after 2 mins. EAS perhaps? I think will have to just go through pulling each fuse in turn until I find which circuit is responsible but I only have a short time to pull/replace fuses one at a time so it may take some time to get through all of them! First though, I might try locking it after closing the door and see if that makes any difference to the current draws before the BeCM has its kip!

Final instalment, I hope.

Hankook holding charge and nice green glow in the peep hole so decided to swap it back in. However, still intrigued by the drain/no drain I decided to run the test by the book. Ammeter connected in series with the negative battery line. Open the drivers door and interior lights come on. Close door and current running at just over 3A until interior lights extinguish then current drops but jumps about between ~1.6A & ~2A and a number of readings in between changing every 1/2 second or so. Two minutes in the current drops to a steady 570mA. At just over 3 minutes the current drops to 35mA as the BeCM finally goes to sleep.

It seems I initially read the reduction to 570mA as the BeCM going to sleep at 2 minutes whereas it seems to finally go to sleep at over 3 minutes. I was confused as when I initially ran the test as I came back just after 2 mins, saw a steady 570mA for 30 seconds or so and thought I had a drain. On subsequent testing I came back after over 3 mins and saw the 35mA so thought the drain had miraculously cured itself! Only when continually watching it today did I see it progressively step down to the final sleep current draw.

No long term abnormal drain but does anyone know why a) the current jumps around before 2 minutes; b) what the steady 570mA draw is; and c) is this step down normal? Reading the formal Iq test it just states for the current to reduce to ~30mA in 2-3 minutes after interior lights extinguish. Well mine takes about 3mins 15 secs!

Mystery solved or the main bit anyway!

Went out earlier to check battery for drain - none apparent. Fired up on first twist of the key and ran happily. EAS very sluggish, so went under the bonnet to witness the EAS compressor struggling somewhat. It then cut out without the pressure switch operating and, on taking off the housing lid, was close to spontaneous combustion having run for only a minute or so! The fuse 40 blowing culprit at last - seems to be seized and not sure whether it just expired or the thermal cut out stopped the action! Took some time to get it out because it was so damn hot! Anyway, spare compressor in and everything back to normal . . . until the next P38 'surprise'!

Can't explain the excessive drain measured, don't think I had a door open or whatever the first time, but it's no longer present.

Battery going flat - I can only assume that because I used it for a few short journey early in December and used the 'Prog' button extensively to defrost/de-ice everything - I did use it a couple of times in succession which was a bit naughty - the alternator output was left funding the heated screens and blowers outrageous thirst plus the lights and not re-charging the battery after the start ups. Left for those few weeks during the coldest weather without much charging and the battery must have slowly, but inexorably, discharged.

Hankook is holding onto the charge so far. I will swap it back in after a few more days if the charge holds up and, fingers crossed, it is is none the worse for its excessive efforts in December.

I have also apologised to the starter motor for besmirching its reputation!

Thanks for the replies.

I put the Hankook on the C-Tek but it just didn't register a battery was there the voltage was so low so it was put on the old charger briefly, just to get it to a voltage where the C-Tek could take over on its specific repair/recovery programme. It's now been moved from ICU to a recovery ward where its voltage retention will be measured before 'discharge' (pun intended) and refitted to the vehicle and put back to work. Time will tell if it was young and strong enough to make full recovery but I've never had a battery recover from such a deep discharge before but they had all been batteries that had been in service for many a year..

What could blow fuse 40 is a good question - only the starter solenoid, EAS compressor and diaphragm valve are powered from it. However, with the fuse blown any continual drain from these items is impossible! I even checked relay 20 to see if it might be stuck on but it checked out OK. Besides which the compressor still seems to be working now, however I will keep an eye on it just in case it is getting a bit ropey (I have a spare reconditioned compressor on the shelf as well). The only thing that is associated with fuse 40 and is permanently connected to the battery is the starter motor itself which is why I am being drawn to it being the culprit - I'm not entirely au fait with its internal workings but I have refurbished a couple of other vehicle starters in the past and can see, despite how unlikely, a solenoid might be kept engaged for a prolonged period of time by the main cog engagement mechanism which might explain the the contacts in the motor/solenoid being connected and drawing current until the fuse just plain overheated and blew. If the main cog stayed somewhat engaged the contacts of the motor may only be lightly engaged leading to not enough current to spin the engine but enough to draw a current. Far fetched - probably but I can't see any other plausible explanation for the current draw.

The only other possibility I can think of is that the current drain is a coincidental and started and ceased at the same time as fuse 40 blew. That seems even more unlikely though.

I last drove Rangie on 21st December and it worked flawlessly. Parked up as normal and then yesterday I came to drive it and the fob would not unlock it so I resorted to the key which unlocked the drivers door only, no central locking ‘unlock’. Key in ignition and absolutely nothing, nada, zip. The battery voltage was 1.7V!!! My less than one year old Hankook MF3-1000 battery is probably toast … sob.

Had to put on my very old traditional, unsophisticated battery charger to get it to take any charge whatsoever. Once it took a bit of charge it was put on life support ‘recovery’ mode of a more sophisticated and ‘intelligent’ C-Tek charger. It is now fully charged but is out of the vehicle and voltage showing good but no idea of capacity yet.

Fitted a back up battery I have that is kept charged and after overcoming the usual annoyance of the alarm going off all looked normal until trying to start the engine. Nothing, no click from any relay or solenoid. Hmmm! Decided to measure the current draw and with everything checked as being off it was draining at ~2A. The BeCM seemed to go to sleep correctly at the 2 minute mark but the drain then sat at a consistent 600mA!

I removed the starter motor relay (16) and bench checked it and all OK. Decided to short the relay contacts in the fuse box without ignition on to check stater motor and nothing, no power at the relay. Pulled fuse 40 and it was completely blown! Replaced fuse and shorted the relay again expecting trouble but the solenoid/starter motor span the engine over fine. Replaced the relay and she started fine, no warning lamps and alternator charging the battery fine. Shut down and restarted a few more times and all OK. Checked the battery drain again and all checked out with BeCM going to sleep and drain at ~30mA.

I can only think the starter solenoid threw a bit of a wobbly and after starting the car for the last time on 21st December then fried the fuse but managed to put the starter into a state where it was continually consuming current. Shorting the starter relay shook the solenoid back to its senses and all is now fine . . . but for how long?

Is my starter on the way out? What mechanism put the starter into a state where it was continually drawing ~1.5A? Is there any other explanation for this odd behaviour? Will my Hankook battery recover its masculinity? Answers on a postcard please!

Slight coolant loss - check the infamous intake heater for crystalline deposits below it on the rocker cover. They tend to leak when the coolant has heated up and pressurised and then drip coolant onto the hot rocker cover from which the coolant then evaporates leaving no liquid but the tell tale colourful dry crystalline deposits are left as evidence.

Oil loss - if the rear engine oil seal is leaking then the bell housing shouldn’t fill up as there is a drain hole at the bottom out of which the oil runs and then down the sump and drips off the sump plug (which can be misdiagnosed as a leaking sump plug). However if crud has accumulated in the drain hole then who knows? Perhaps check the drain is ‘clear’ of debris.

Morat wrote:

And the they discovered SAP and the beancounters got their fangs into the engineer's budgets. :(

So true. The W124 was the Zenith of Mercedes engineering and build quality but that was an early 1980’s design. The P38 is an early 1990’s design and, by that time, Mercedes had started on the slippery slope of reducing quality to match the ‘state’ of its competitors.

However, c’mon JMCL did you manage the delicate surgery or is the fan now toast?

To be fair to LR their plastics are no more shitty than anyone else’s and they really only design for a product life not exceeding 10 years. When dealing with 20 year plus plastics then some brittleness is to be expected no matter who the manufacturer is. However, the advice to be very, very gentle is to be taken seriously and not to overtighten on reassembly.

My fan/sensor went AWOL some years ago and no amount of vacuuming and cleaning would rejuvenate it so it was replaced - pretty easy job. It’s output must have failed high as it was summer and the air con just kept trying to cool the cabin no matter what reasonable temp was selected on the HEVAC. It was a long journey back from Cornwall on a hot day and we initially froze before a very manual air con on/off/on/off cycle was invoked to get some semblance of comfort in the cabin.

That’s not how Wabco D operates, well not how mine works. If you have replaced a faulty sensor with a good one then on start up the ABS and Traction lights will extinguish as normal but the system ‘nags’ you via the DIS of the Traction Failure (which isn’t there anymore) and then proceeds to erroneously nag you for a few seconds of a non existent Traction Failure when you subsequently switch the ignition off. I assume this is because the Traction Failure is logged in the Wabco D unit and will not reset until the next power off/power on - seems a bit of an inbuilt software oddity. When you subsequently restart all the warnings are reset and normality resumes - no lights, no DIS nags. If you continuously have a Traction Failure warning then that’s something other than a repaired faulty sensor!

For the Wabco D system (don’t know about other previous systems) when a sensor is replaced the power on self test will pass for ABS but the Traction warning in the DIS will remain until the vehicle is driven and then shut down and then restarted at which point it, too, will go away.

As part of my set of ready use spares I have one rear and one front known good ABS sensor on the shelf. When I get the ABS/Traction fault on POST I use Nano to identify if it is a sensor and, if so, I use a spare sensor to just plug in (not fit) in place of that sensor and check it clears the POST fault before going on to dig out the old sensor and permanently fit the new one. I then purchase a replacement for the used spare and at least check it passes POST before storing it on the shelf.

I fully support Richard’s view that a second hand OEM Wabco sensor is preferable to a new aftermarket sensor as I have had no end of problems with short lived aftermarket sensors lasting only a few thousand miles before failing for no good reason. If only I knew where to get reliable second hand sensors or whether Wabco do an OEM sensors but not in Land Rover packaging!

The nano is, as you say, a bit ‘dyslexic’ regarding the voltage measurements but because it just reports the fault in the Wabco ECU verbatim it is accurate with regards to which sensor has an error.

Edit: Just checked and wrt the right front the nano is actually correct with voltage measurements as well - it’s the only one though!

Edit 2: According to RAVE there are no connectors twixt the Wabco ECU and the wheel sensor flying leads.

Most probably. Under that screw 'hole' in the small plastic scuttle cover there should be a press in square plastic housed captive nut. The hole for the captive nut assembly goes directly into the pollen filter housing below. The plastic housing has a gasket under its 'shoulder' to seal it but mine had disintegrated. When you screw into it it naturally lifts the plastic captive nut housing upwards and water leaks under the 'shoulder' and into the pollen filter housing and from there under the dash and into the footwell.

Options are a) make another small gasket from neoprene sheet or similar; b) 'glue' the captive nut assembly in position with RTV; or c) buy a new replacement captive nut assembly.

Water leaking under the dash on the driver’s side.

I suspected the pollen filter housing might be leaking through the cover so made (another) gasket for the cover. No change, still leaking.

I pulled the pollen filter out but it looked OK and dry so I was somewhat perplexed at where the water ingress was occurring so I taped around the windscreen on that side to exclude a windscreen leak but it still made no difference.

I had heard that water can ingress via the screws that hold the small plastic scuttle pieces in place so I removed the easily accessible one and, yes, it’s threads were wet. I injected some clear RTV into the screw hole and ensured the flanged head had RTV under it as well. Made no difference.

I pulled the windscreen side and bottom trim off and the small plastic scuttle trim off that side. Bit dirty underneath but all still looked OK. I again pulled the pollen filter and, again it looked OK . . . until I tipped it sideways and water ran from within its folds. I then examined the housing more closely and, yes, there were signs of moisture in there. I pulled out the plastic captive nut that protrudes into the pollen filter housing and examined it. It still seemed intact and had not split anywhere but the small seal under its collar where it plugs in had disintegrated. I reinstalled it but with RTV sealer under the collar and a ring of RTV externally around it so it was sealed from moisture once the small scuttle panel was reinstalled. Dried out the pollen filter and it’s housing and reinstalled filter and cover. Problem sorted.

I have had a similar issue with ABS in that nano reported wheel sensor voltages OK and speed readings were apparent from each sensor but the ABS and Traction faults were still flagged up on the dash. However, nano did tell me a wheel sensor was at fault. It turned out that the resistance of that particular sensor was higher than the other three but not spectacularly so. Changing the sensor cured the fault.

I concluded that the static POST of the system measures the resistance of each sensor (probably by current draw) and flags a fault if out of spec.

In your case the fault is may be ‘lodged’ in the ABS ECU unit and needs clearing - there is a fault there as that is what triggers the dash indications. The faults clear themselves in the WABCO D unit the system is rectified but I am unfamiliar with the workings of earlier units.

Mine are more duct tape than anything else these days. If you get spangly new ones then it’s worth duct taping all around at the edges on the back. Then seal them to the door with non drying ‘goo’ of choice on this duct tape and the vapour barrier won’t rip to shreds when you next (have to, and you will) take it off or release it in places to change the door lock / sort the internal released mechanism out / replace the regulator*

*Delete as appropriate.

Simple way to detect a leak - tape a short length of tissue paper to the end of a stick with about an inch protruding over the end and then go round the manifold and joints. The tissue will flail around even at the slightest leak. May need to stall the fan or at least shield the ‘test probe’ from it during the test. The beauty of this method is you don’t burn your hands and you can get right around the manifold to downpipe joints with ease.

If manifold bolts need to come out plus gas and patience are the order of the day. Soak bolts thoroughly hours before you attempt the job and then start with a (very) small tightening to barely move the bolt and then it’s very slight loosening before very slight tightening and continuous rinse and repeat with the loosening being just a bit more than the tightening until the bolt frees and can be taken out. It takes time but not as much time as trying to remove a sheared bolt!

I have had two (of the many) ABS/Traction faults that have been ‘out of the ordinary’.

The first was a broken reluctor wheel on the hub. This was only diagnosed by jacking the car up and hand spinning the wheel and measuring the sensor output on an oscilloscope. There was still an output but it was ‘odd’ compared to the other three. Testing of the ABS sensor itself yielded nothing untoward - it’s resistance was the same as the others and it was giving an output. Looking down the ‘hole’ for the ‘odd’ output sensor and slowly rotating the hub did indeed show a broken reluctor ring. Hub replaced (pretty cheap and a lot easier than ‘sweating’ a replacement reluctor ring onto the hub) and peace and harmony was restored.

The second was flagged up as a normal sensor fault on NanoCom. However it’s supply voltage was normal and so was the speed output. However it’s resistance was a bit higher than ‘normal’ - not a lot but definitely higher than the others. Changed it and, again, all was well. I deduced from this that the POST by the Wabco unit tests the resistance of each sensor (current draw?) and if outside prescribed limits flags a fault.