QuestionQUESTION: Hi John,
Welcome back from vacation. Thank you for your time.
Background: I have a 96 Range Rover 4.0 with 140k. I have owned it since 90k with no major issues. I spent 5 years working in a repair facility before switching careers, so have a decent mechanical aptitude but am hitting a wall with the current issues.
Problem: About 3 months ago, started experiencing odd electrical issues within the central locking system.
1st incident: buzzing in RR door lock actuator. Pulled panel and unplugged actuator, left vehicle for the night, came out in the morning to stone dead battery. Jumped car, plugged in actuator, and there was no noise..problem seemed to be gone. No issues for 4 weeks
2nd incident: Got in vehicle, shut door, and car went into lockdown mode. All locks kept cycling about every two seconds. Tried to start and car was immobilized, wouldn't turn over. "Trac off" message was on display. Locks continued to cycle. Was able to unlock and open door quickly between pulses. Had car towed to shop, where the locks continued to cycle until battery drained. Car sat overnight. Charged battery in morning and car started right up and all locking issues were gone. Was fine for 2 weeks, no issues.
3rd incident: Same as incident 2. Drove car to work, came out end of day to find the locks cycling. Disconnected battery, left overnight. Following day, connected battery, started right up. No issues. Drove home and disconnected battery before issue started.
So! Here we are. Based on everything I've researched, all signs point to faulty BCM. Everything I've read, though, indicates you should inspect the under hood fuse panel first. So took it apart and did so and found multiple burn marks on the board as well as fair amount of white corrosion stains. So I went ahead and replaced the board with OEM part. Car started fine and have not had the locking issues I was before and have been driving it for 2 weeks. However, there is a host of new issues that have been happening immediately following board replacement:
1)Remote locks don't work, yet central locking does when turn the key in driver door...except the RF door lock doesn't go with the rest.
2)Tailgate actuator signal is very weak. Barely unlocks the upper lift gate. If you hit it again to lower the tailgate, it does not work at all.
3)Rear wiper inop. Will move about 2 inches then stop.
4)Dash, center console, and window switch illumination stay on. Only way to get them off is to pull fuse.
5)Rear door amps have weak/sporadic signal..sound will come through but keeps cutting out.
6)MIL on, only since board replacement
7)Message indicator cycles Fuse 9 and Fuse 15 failure, but fuses are intact.
So what do you think of all this? Again, it screams BCM, but I find it odd that so much changed after fuse box replacement. I appreciate your insight.
Thanks
Jon
ANSWER: If the truck were here I'd fit a test BECM and see what happened. You can spend forever chasing those things one by one, so the BECM swap is the easiest and most direct diagnostic step.
Remember that you need a T4 or Autologic system to program a BECM and if you swap it you need to resync the engine ecu security before the vehicle will ruun
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QUESTION: Thanks John. Roughly how much would you charge to perform the diagnosis?
Thanks
Jon
AnswerYou ask what I would charge to test-swap a BECM. Here at Robison Service we actually stock a swap BECM just for situations like yours. To swap it you have to pull the instrument cluster so the mileage reading does not change. You'd spend 2-3 hours doing a test swap which will give a sure answer to this problem.
If you look for a company where you live remember they would have to have a swappable BECM, and the coding tools to try this out. Make sure the shop you select has the resources to do the swap. What we'd do is swap it out, and if that works, we'd overnight a permanent replacement and fit it the next day.
