Rover 75 KV6 automatic gearbox problem

[robimo]

Originally Posted by vitesse

Great that you’ve got Toaf working (and presumably got home) and it reports CAN bus errors. I believe the EGS1 relates to the gearbox connection and the others the main ECU (or EMU), trouble is it mean little to me, might as well be Greek (or Italian).

Try reading through previous posts, like the one I linked to. I’ve not had this kind of problem but remembering old posts they had to identify the CAN bus header and trace backwards. As these errors are all in BMW speak try your local BMW agent.

Good luck

Thanks for your help.
Unfortunately I'm still on vacation, not at home.
Yesterday I cleared the error codes with Toaf and drove the car about 10km without any problems.
On return I tried with Toaf and no error code.

Regarding your advice to go to a BMW agent, I don't know in England, but in Italy, apart from some old generic mechanics, there are only large workshops left.
If I go with an old Rover to a BMW agent, they laugh at me and don't even look at it.
They are full of work and certainly want to avoid complicated jobs that are deemed low-paying.
I hope to be able to go home and that the old mechanic I usually go to will help me.

[robimo]

Originally Posted by Mike Noc

When the D failed to light up did EP show up instead or was the display blank?

No, the display blank, also "check engine" light was down.

After about 1 minute, the tachometer, the water temperature, the air conditioning no longer worked, "Traction control" light up and the car was not going more than 50/60 km per hour.
The speed gauge and the fuel gauge worked.

[robimo]

I would like to check the gearbox control unit connector.
I saw that the gearbox control unit is under the passenger's feet, but I've a LHD car.
will the gearbox control unit be on the left under the driver or right under the passenger?

[vitesse]

Originally Posted by robimo

I would like to check the gearbox control unit connector.
I saw that the gearbox control unit is under the passenger's feet, but I've a LHD car.
will the gearbox control unit be on the left under the driver or right under the passenger?

Looking at a photo (from Arctic of course) the location seems to be mirrored, so in your passenger's footwell.

If you don't want to go to a BMW dealer try and find a local BMW club as some private guys know more about the cars than the main dealers, or a specialised Auto Electrician - the electronics are very similar to early BMWs. All the electrical diagrams are available on this forum, including lhd cars.

I hope you've searched this forum for CAN bus faults and got some idea of the problem.

Good luck

[robimo]

Thanks, good idea to try contacting a local BMW club.
At home I have the service manual and I should find the electrical diagrams.

There was a strong storm last night, this morning I tried to see inside and in the trunk, but they are perfectly dry.
I drove the car for a few km also this morning and everything is ok.

I bought a WD-40 contact cleaner and I want to try cleaning the ECU contacts in the hood
and of the gearbox contro unit.
I am not a mechanic, but I have a minimum of manual skills.

[SD1too]

Originally Posted by robimo

No, the display blank, also "check engine" light was down ... the tachometer, the water temperature, the air conditioning no longer worked ...

Hi Rob,

This is very useful evidence. I think you should look at the instrument pack wiring connections as it acts as a CAN bus communication "gateway". It's common to all the fault symptoms you have given:

• Tachometer and temperature gauge failure indicate loss of communication with the ECM.
• The PRNDL display loss indicates loss of comms. with the automatic transmission ECU.

It's therefore unlikely that you have experienced simultaneous failure of two separate ECUs. Your gearbox is misbehaving because it's unable to communicate with the rest of the CAN bus system.

When you say that the "check engine" light is "down", do you mean that it is illuminated continuously?
Has any work been done on your car recently which might have resulted in wiring damage or a displaced connector?

Simon

[robimo]

Originally Posted by SD1too

Hi Rob,

This is very useful evidence. I think you should look at the instrument pack wiring connections as it acts as a CAN bus communication "gateway". It's common to all the fault symptoms you have given:

• Tachometer and temperature gauge failure indicate loss of communication with the ECM.
• The PRNDL display loss indicates loss of comms. with the automatic transmission ECU.

It's therefore unlikely that you have experienced simultaneous failure of two separate ECUs. Your gearbox is misbehaving because it's unable to communicate with the rest of the CAN bus system.

When you say that the "check engine" light is "down", do you mean that it is illuminated continuously?
Has any work been done on your car recently which might have resulted in wiring damage or a displaced connector?

Simon

The "check engine" light did not come on but remained off, but the car did not go more than 50/60 km/h.

I use the car occasionally, it is not my main car.
I haven't had any work done in at least 2 years, for this reason I think it may be oxidized contacts, not damaged cables.

I'm not a mechanic, when you say "I think you should look at the instrument pack wiring connections" which connectors do you mean?

Now I am far from home and my goal is to be able to go home next Tuesday.
For the moment the car hasn't given me any more problems, I hope in god.
If I can have directions to give to the mechanic at home, thank you in advance.

Now, I'm thinking to try cleaning the ECU contacts in the hood
and of the gearbox contro unit

[BigRuss]

Yes sounds like you've got a CAN-bus issue.
It's going to be a wiring problem, the thing to do is look at what's working and what isn't.

If the coolant temperature guage and rev counter are working then the CAN messages are getting through to the instrument pack from the ECM. If it's displaying the selected gear then the CAN messages are getting through from the Autobox ECU.
The problem with the CAN-bus is that if a message doesn't get through when it's requested or sent and it continues to try and send/ receive that message and effectively it can block the system or parts of it.


The Autobox relies on engine speed information via CAN from the ECM in order to decide which gear is required, it also receives information via CAN from the ABS ECU for road speed.
This also goes to the instrument pack so if the Speedo is working then the CAN is intact between the ABS and the instrument pack.
In other words the instrument pack is ok if that is the case.

The first place I'd stay to look is check and clean all the fuses in the passenger compartment fusebox especially if it's 2003 or later (red fuse box ),the micro- fuses tarnish and lose contact. Also check the fuses under the bonnet. (If a power feed to one of the ECU'S is missing that supplies the CAN system then it can't operate.)

Look at the two large connectors for the Autobox just in front of the suspension turret , separate them and make sure the contacts are clean. Also check for wiring damage.

Then look at the connections to the under bonnet fuse box and the wiring beneath it. To do this properly you will need to remove the fuse box.

Look for any signs of damage to the wiring the CAN is a twisted pair of yellow wires one with a black trace the other brown. Fine grit can get deposited onto the wiring and eventually it breaks through the plastic sheath. The wire corrodes and can cause intermittent problems. Eventually the wire will fail completely.

Corrosion shows up as a greenish deposit on the wiring and it may be noticeably more flexible at that point. If found then the corroded wire needs to be cut back to a point where it's clean and then re-joined.

Note that if it's the twisted pair then it can be untwisted to enable the repair but the untwisted section needs to be kept to a minimum to ensure correct CAN operation.

Russ

[robimo]

thank you very much.

I will try to check the fuses in the passenger compartment, those in the hood and to remove the box.
Let's see what I find.

[SD1too]

Originally Posted by robimo

I haven't had any work done in at least 2 years, for this reason I think it may be oxidized contacts, not damaged cables.

A very sound theory Rob!

Originally Posted by robimo

I'm not a mechanic, when you say "I think you should look at the instrument pack wiring connections" which connectors do you mean?

I was thinking that you might withdraw the instrument pack to re-seat all the connectors to it.

You seem to have partial loss of CAN bus comms. not total, and the fault is intermittent which makes it harder to trace, but I think you're on the right lines.

Simon