[bmwrovers]

Ok, at first it was just annoying... Now it's down right frustrating! We have issues... Driving down the road and the doors lock and unlock, four ways start flashing, radio/nav/and hvac all turn off. Suspension doesn't drop but the system is unresponsive and says "shutting down"... The truck still drives and sometimes, it randomly goes back to norm, but keeps doing this! Often times then it won't start, especially if it was in one of these episodes when shutting it off. I've replaced the battery, brake light switch and ALL the light bulbs are LR (a small fortune in bulbs).... I've taken apart the tcm and interior looking for corroded wires or such and nothing... Any other ideas???
It is a 05 with 46k on it.

 

[cnfowler]

It could be a short somewhere or a pinched wire. Unfortunately, that's fairly common in the electrical-laden Land Rovers.


Colin

 

[RoverGuy7]

The locks cycling, and hazards activating is the vehicle going into 'crash mode'

On these trucks, instead of the SRS unit telling everything else that there has been a crash, it is constantly telling everything that there hasn't been one, until there has. If the communication network, HS CAN Buss in this case, fails then everything assumes that there has been a crash.

You're looking at either a wiring issue, or one of just a couple modules failing. The way the CAN is set up, it needs to be a specific module in order to cause this.

Remove the vehicle battery, there is a plastic cover behind it, and your transfer case control module inside there, 3 colorful connectors on top. Check for corrosion at the connectors and the ECU. Most common place for this kind of failure, other modules that can cause this are... engine ECU, EAS ECU, ABS ECU, Rear diff ECU, Instrument pack.

 

[bmwrovers]

yeah i looked at the TCM, looks ok... it was pouring rain over the weekend and i looked to see if water was there, just as a backup... bone dry. i'll have to start checking other ECus now... where would the CAN be located? or is it not that simple.

 

[RoverGuy7]

The CAN bus is wires. Yellow and black, and yellow and brown, twisted pair that runs through out the entire truck.

I forgot parking brake ECU from the above list.

The diagnostic process should be to monitor CAN voltage, easily accessed at the DLC, and watch what voltage does during failure.

 

[bmwrovers]

well after a few nights of further ripping apart the interior... i narrowed the faulty location to be the instrument cluster area... took the cluster out, all the soder joints look good, no burn marks, took apart the electrical connector and all the pins are ok... put it back together and we'll see...

 

[RoverGuy7]

Sounds like the IP will need replacement, seen that a few times.

 

[racehorse]

Appreciated

Sounds like the IP will need replacement, seen that a few times.

Dave

Any time a tech spends time helping to diagnose is a very cool - and appreciated effort. I always think you guys go underappreciated when you are willing to chime in and help out fellow rovers online.

Well done and thanks for the consistent help to folks on this forum and others by all the techs out there.

Mike
Member, SCLR
06 LR3SE

 

[bmwrovers]

Yes thank you Dave! Any help is much appreciated!!
Back to the drawing board, today it was worse, spending more time in "error" flashy mode than normal.

 

[RoverGuy7]

The IP contains one of the terminating resistors for the HS CAN bus. I have seen a few of these fail intermittently and cause what you're seeing. You were exactly right, tapping on the cluster was the way I first traced down the failure the first time I saw it (after extensive tracing, and diagnosis.)

 

[bmwrovers]

Solution? is there a way to find the resistor and repair or am i looking at a new IP?

 

[RoverGuy7]

I have never taken one apart and tried. You can check it, however, a resistance reading is worthless with voltage on the circuit, and it being intermittent, you wold have to check during a failure, but with everything powered down, might be tricky. It is a 120 ohm resister, with another in the ABS?(can't remember off the top of my head, it was changed several times over the years) wired in parallel, to give a high to low side of the high speed can a resistance value of 60 ohm(generally 62 when testing, as wires aren't perfect)

The only repair that I have done with this failure is IP replacement. Everything in there is SMD, so I don't know how much is 'repairable' without the right equipment.

That said, with the board apart, and checking from high side to low side, you may be able to trace down the resistor, and replace it, if you're real good with very small electronics.

 

[bmwrovers]

anyone have any luck with just removing the "fuse" for the hazard lights? i don't mind driving around without ac or radio for now, but i think the hazards flashing is more annoying to other drivers. i am reading thru the diagrams and don't see a specific fuse for them, just link 16e, but it terminates to master lighting, so i'm not sure i want to remove that.

 

[bmwrovers]

UPDATE!!!
I pulled the cluster out again and scowered it with magnifying glass again to look for burn/bad sodder... nothing... so i pulled the connector apart again and messed with wiring... nothing looked bad, we HAD to use the truck yesterday on a trip to baltimore, so i put it back in without screwing down the cluster, just left it "float" there (asking the wife to be very careful not to bump it as it was in working mode without errors). the truck ran smoothly all the way down and back! hopefully i can put the cluster in officially and the problem was just a loose connection and not the board itself!

 

[bmwrovers]

Update: After a few weeks of fighting with the cluster floating in the car (unbolted and dash surround apart), so when an "episode" happened i could move it around to make it normal again... i finally did some further disgnostics... ie. poking and proding... it appears the connector was very loose (probably throwing off some of the pins), so i wedged some cut off zip ties in there as shims and it appears to work fine now! 2 weeks of driving around ok. i guess that was the problem! just a loose connection! hopefully.