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Discussion Starter #1
All,

I have searched the forums and have not found anyone that has had these problems. I have a 2002 P38a, by the way. Following are details:

Long-Term Symptoms
  1. Intermittently, pressing tailgate button triggers a lock dance and the tailgate does not unlock.
  2. Intermittently, the locks in the vehicle just lock and unlock
The above issues were worse before I replaced my engine fuse box. However, they have slowly returned.


Recently Appearing Symptoms
  1. Upon starting the Rover, the stereo, HeVAC, windows, seats, and whatever else is controlled by fuses 8, 9, 10, 20, and 22 do not work. Note that the HeVAC head unit display is illuminated. However, there is nothing displayed and the blowers do not work
  2. Fuse 8, 9, 10, 20, and 22 failure messages show up at the message center
  3. Upon turning off the vehicle, the HeVAC blowers come on and I believe only the front locks do not work. When I lock and unlock using the key fob, the HeVAC blowers go off
  4. Due to some of the locking craziness, I get some Engine Disabled and Ignition Tamper messages. However, I believe these are just due to my having to start the car after the alarm system was artificially triggered
  5. If I drive the Rover around, the HeVAC blowers eventually come on and speed up and slow down along with the engine revolutions
The above problems has occurred a couple of times over the past few months. However, it has become more consistent over the past couple of days.

Electrical Test Results

  • Engine off, all accessories on for 30 seconds, then off. What voltage______
12.2

  • Voltage across battery at idle (no electrical load) ____________
14

  • Voltage across battery at 2000rpm (no electrical load) ________
14

  • Voltage across battery at 2000rpm (everything electrical switched on) _________
13.9

  • Voltage at ALTERNATOR at 2000rpm (everything switched on)___________________
0

  • Voltage drop between alternator body and battery negative (YES negative). Measure at max electrical load and 2000rpm ______________ (millivolts please)
50

  • Voltage drop between alternator positive and battery positive. 2000rpm, max electrical load _____________
27

  • Check Voltage drop from Battery Negative terminal to 1st groundpoint on vehicle______________
1,3,4.5

  • Check voltage drop from 1st ground point to block__________
41

  • Check voltage drop from Alternator Housing to block__________
0

  • Voltage from alternator positive to alternator housing
13.9

Note that I could not necessarily turn on all electrical equipment due to the fact that the listed items controlled by the BECM and interior fuse box are inoperable.

I am currently suspecting that it is the BECM ground. Prior to my going after it, I am seeking advice. I cannot adjust the seat due to it being inoperable.


Thank you!
Jon
 

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It sounds BECM related.Whether it is earth,connector,fluid contamination,corrosion or just BECM electrical failure remains to be seen.
 

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Discussion Starter #3
Follow-Up - I just looked at the BECM connections through the fuse box opening to the right of the passenger seat (LHD vehicle). I could not see any evidence of corrosion or anything. Am I barking up the wrong tree with the BECM? I have no reason to believe that it is the BECM except the symptoms. There haven't been any spills. I detect no moisture down there. There is no evidence of my heater core O-Rings leaking. Currently, I feel like this will be an exercise in disconnecting everything, reconnecting everything, and then hoping for the best. I am currently not buying it. Is there a second earth lead attached behind the BECM or is the only earth lead the one on the side?

Thanks again!
Jon
 

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1995-2002 Range Rover P38A
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I'm afraid this looks like a BECM internal problem, based on what happened to mine....but it is worth doing the simple stuff. All of the earth leads are worth checking and cleaning - use the workshop manual for their locations. By the way, BECM internal corrosion has been linked to having the car valetted internally as well as to the O ring problem that I had. If you are worried about a BECM internal rebuild, it is not as expensive as you might think. Try sending a PM to Rick-the-Pick on this forum, or wait for one of the US guys who do it to pop up.
 

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Discussion Starter #5
Thank you for the response. I will keep that in mind. After exhibiting the problems last night and this morning, all has been well mid-morning and on, today.
 

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check for wire harness chafing in the area of the underhood fuse box.the alarm sounder area is a good place to start also check that the wire terminals are not backing out of the connectors for the under hood fuse box. i have seen this harness routed too tight and causing strain on the terminals. agood wire harness wiggle test is all thats needed to verify if it's a poor connection.
 

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Could be chaffing related, i've found heaps of spots under the bonnet (especially the power wires to the eas pump chaffing on the soloniods). The power feed wires that go to the BECM sit quite tight under the plastic seat base pannel.

All the fuses you listed come off maxi fuse 5. Your cigerette lighter, and rear auxilary socket shouldn't work either.

these fuses run the front door outstations, and the seat memory switch stuff.

Your immobiliser and locking will be all over the place, as the BECM cannot communicate with the outstations.

If MF5 checks out okay, i'd be double checking that you've got the right model fuse box before condeming teh BECM. Was it a second hand fuse box? YQE103410 is what you should have if it's a v8. There should be a sticker on the front of the lower box.

It sounds to me as if your origional problem started with the right hand front door outstation, which supplies earth to the rear tailgate motor. You can take out the lock too, and have a look and test the two micro switches in there.

I havn't got any diagrams now (at work), i'll try and trace the fan problem tonight when I get home.
 

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Discussion Starter #8
My goodness. A thousand thanks for the responses. I will check out these many possibilities tomorrow.
 

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Discussion Starter #9
By the way, my current hypothesis is that these problems are happening due to a weak battery. The craziness was occurring when we let the rover sit over the weekend. Now that I have been driving it regularly again, the problems have not show up. I will let it sit again this weekend in order to see if the problems return. I will also check the potential problems previously listed.


Thanks again!
Jon
 

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Discussion Starter #10
Some new data has emerged that speaks against my weak battery hypothesis. Previously, I thought the problem was only occurring at start up. It started up fine this morning. After driving for about 8 miles, the craziness occurred for about 30 seconds and then went away.

It must be a connection somewhere.


Thanks!
Jon
 

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Discussion Starter #11
I checked the maxi fuse 5 as well as the engine fuse box model number. All is well. Yes, it is a second hand unit.

I decided to inspect my batter a little closer. There is corrosion on the positive terminal as always. I'll clean everything up which should help.

In inspecting the battery, I did notice and recall that I had to purchase after-market terminals because the battery I had only had screws. Has anyone ever noticed these screw-on terminals to have any ill-effects? When I unscrewed them, there didn't appear to be any signs of corrosion or poor connection. Thoughts?


Thanks!
Jon
 

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I've had trouble with battery terminals too, like buying a huge new flashy battery, then finding the positive and negative swapped around...:oops:
I've also had to clean up the maxifuse connection studs on the BECM, and the Earthing point on the floor behind the BECM and the base of the A pillar behind the kick pannel. The car also needed a new heater core, so I assume the coolant that leaked out sat there and caused the corrosion.

When I bought mine it'd been sitting around for near on 12 months, and the rear tailgate wouldn't work (along with the indicators, and left headlight); but with the new battery and a bit of use they all come good.

Did you get get the fuse failure messages at all? What other lights / messages did the instrument cluster say?
 

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Discussion Starter #13
On my way home from work today, the craziness happened again. Fuses 8, 9, 10, 20, and 22 failure messages were displayed. The front windows did not work. The HeVAC head unit and fans did not work (due to the head unit). The cigar lighter did not work.

One item I failed to mention was that I had modded my Rover to house my Garmin Nuvi 350 GPS in place of the Navigation display. I did not disconnect the navigation since it affected the stereo. I mounted the GPS on the face of the display, drilled a small hole on the side of the nav display to run the power cord, removed the cigar lighter and set it back behind the fascia, connected the power cord to the cigar lighter, taped it up for stability, and then plugged the cigar lighter hole. I did this a couple of years ago.

Tonight I reversed that modification back to as close to normal as possible.

I am assuming my heater core O-Rings are about to go. I do not see any fluid appearing in the passenger footwell. However, every now and then there is a congealed build-up of what smells and looks like condensed coolant underneath the fascia in the passenger footwell. It is not much at all. However, I am wondering if I have a slight spray through failed O-Rings every now and then. It looks like there is a build-up in the cigar lighter. Perhaps I had a short? I am wondering if the reversal of the modification will fix my issue.

In addition, I have another post about my blend flaps appearing to stick a bit. They still work. I wonder if some of this coolant is spraying and condensing at the blend motor and making it stick.

As always, I will keep posting until resolution presents itself.


Thanks!
Jon
 

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Discussion Starter #14
Benji,

When you state that you had to clean up the maxifuse connection studs on the BECM, was it because you could visibly see some sort of corrosion or liquid? The connections I can see through the passenger seat fuse box are clean and shiny. I am not motivated to do anything with them.

The earth point behind the passenger seat on the floor board is my next suspect. Although, I am not going to do anything unless the issue presents itself again. I did make those changes yesterday and want to make sure those don't fix the problem before I investigate further. Did you see any evidence of failure at that earth point?

You mention that coolant got down near the BECM and the earth point. How is that possible? Would the coolant run through the center console under the carpet down to the BECM area?


Thanks!
Jon
 

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1995-2002 Range Rover P38A
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I had soaking foam under the drivers side carpet, from a leak heater core connection. One way of checking it would be to remove the plastic sill trim from the bottom of the door, and then you'll see the main electrical looms running in the door sill by the BECM...

On my RR, there was evidence of moisture in the sill and pressing on the carpet caused coolant to drip out of the foam...

If you don't have that much coolant present, then I also managed to get my hand up under the carpet and feel how wet the foam was.

Once you get coolant under there and it soaks the foam, it's just a matter of time before it seeps towards the BECM. I'm pretty sure it was the source of my corrosion on the BECM board that ended up having one of the windows not working properly.

Also something to note.. I didn't have any real discolouration of feeling of dampness on the carpet (I looked for those tell tale signs before buying it), and it was only after getting the plastic door sill out and feeling the foam underneath and seeing the coolant bubble out that I found out what i was...

Let us know how you get on!

Cheers,
Marty
 

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Discussion Starter #16
Thanks you Marty for the illustration. I will perform that check. Thanks to all who have responded to this post.

I meant to get to removing my passenger seat (LHD vehicle) during this long weekend however my yard chores took priority. Since I reversed my GPS modification, I have not seen the problem return. My locks are still going crazy, though.

I will keep this thread updated with the resolution. Right now, I am thinking about checking in order the ground behind the BECM, driver's door lock connections, tailgate latch connections, and passenger front door lock connections.
 

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Discussion Starter #17
Update: I removed the passenger seat to reveal the BECM. It was actually pretty easy to do with the Torx T50 bit. I also cleaned up a bunch of junk left over from the previous owner. I bought the rover in 2008. There was some gunk on top of the BECM which I cleaned off. I did notice some discoloration in the carpet under the seat. It was a bit darker than the exposed carpet.

Electrically, I have checked all external connections around the BECM. There is no evidence of any type of moisture or dampness around the unit. The ground behind the BECM is clean and tight. I did not mess with it. The connections on the side of the BECM are also clean and tight.

My issues may have whittled down to just the door locking and tailgate issues. I have not seen the crazy fuse 8,9,10,22, and 24 faults since I reversed my GPS modification. This isn't to say that they are gone. They just haven't shown up in about 10 days worth of driving.

So, my door locks kind of go crazy frequently and this has happened as long as I can remember. They improved once when I changed my engine fuse box out. However, they have slowly returned over the past year. The locks actuate whether I am actively driving or not. The rover can be off and they will actuate (I have not tested as to whether or not they actuate when the key fob is out of range).

As for the tailgate, it quite frequently disables. I eventually get it open by continuously pressing it. When I do this the other door locks lock and unlock. I press the buttons on the key fob to unlock them when they lock. I repeat this process until the tailgate eventually opens. Hilariously enough, it always eventually opens.

I have done/noticed the following:

1. I have checked the grounds near the rear seat seatbelt mechanisms. They are clean and tight.
2. I have noticed that there is a female-less white connector under the engine fuse box and next to the security alarm horn.
3. I noticed that one of the defrosters was disconnected from the right-side luggage space window. I pulled it further away from the window so there would be no chance of intermittent connection.
4. I checked the front passenger door outstation just for kicks and all seemed fine.
5. From a previous effort, I had cleaned up my battery connections

Sorry for posting this prior to researching the board. However, next I am going to research the board as if these are my only issues.


Thanks!
Jon
 

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Have you considered that your lock fob is faulty and causing the problem?
 

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If the lock fob were faulty it would have no bearing on the tailgate button nor would it trigger the usual "lock dance" associated with a failing passenger latch.

I'll toss in a vote for a frayed wire that will be close to impossible to locate since pretty much every other chance has been eliminated.
 

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Discussion Starter #20
BECM looked immaculate. No evidence of moisture. I pulled the plug that serves the right hand door and tailgate and there was no evidence of shortage, corrosion, etc.

I took a closer look at the connection for the alarm sounder. One of the wires is severed. I sat in the back seat with the rover super locked and nothing ever happened when I moved around. In our discovery, the alarm goes off if you do that due to the glass break motion sensor. I started the ignition and the engine was shut off, as expected.

Tomorrow, I am going to repair the alarm sounder connections. I am hoping but doubt this has something to do with my door locking issue.
 
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