THREE ELECTRICAL ISSUES THAT I THINK ARE CONNECTED

[Heyes965]

Hi, iam new to this forum & would appreciate a little advice.
Around a week ago, i put my 4200 in reverse & the gearbox light came on & i couldnt get the car in reverse, i drove around a bit & then it went into reverse & the light went out.
Since then i have no reverse lights, no parking sensors & mirrors dont go down when in reverse.
Ive taken out the reverse gear selector switch & found the reverse gear knob/stick has two lugs missing & have replaced this & still have the same issues, i have plugged into texa & it has
come up with reverse light switch, but this is part of the reverse control unit.
Anyone else had these issues & has buying the control unit @ £1200 plus vat sorted it?

Thanks
Kevin

 

[Navcorr]

There are a few threads, here & on ML, where similar symptoms are discussed. Someone here a while ago started to disassemble the switch unit but not sure if it was fully documented. Where about are you based? Perhaps, if possible, trying another unit first before shelling out would be a starting point. Bear in mind the early models, units with the two screws, have a different loom connector to later models. Welcome by the way.

 

[Heyes965]

Iam in toddington, iam going to take the switch apart over the weekend, but looking on the back there are only 4 circuits, one to the auto switch, another to the ice switch & 2 to the reverse & ive checked & they have continuity. Ill have to out some power to it.

Iam starting to wonder if there is a problem down the line.

Where on hear did you see those threads?

Thanks

 

[Navcorr]

From memory - but the search function is often your best friend. Top right hand corner. Cross referencing with Google also helps.
Think it was a GS selector being taken apart, iirc, but possibly very similar internals.

 

[Heyes965]

Thanks, iam taking it apart later & will report on how i get on

 

[Steve4200]

Thanks, iam taking it apart later & will report on how i get on

The actual REV signal comes from the Gearbox ECU when it sees the gearbox in actually engaged in REV and not based on the REV Switch console request.

 

[Heyes965]

Have you had this before? & can the gearbox ecu be fixed?

 

[Steve4200]

Have you had this before? & can the gearbox ecu be fixed?

It could be many things , faulty ECU would be last on the list. What fault code number is the TEXA showing ?

 

[Heyes965]

I will have to look again as didnt jot number down, but it can up with reverse light switch

 

[Navcorr]

The actual REV signal comes from the Gearbox ECU when it sees the gearbox in actually engaged in REV and not based on the REV Switch console request.

I wouldn't wish to question any of this, particularly in view of your excellent work reverse engineering system codes, I do recall though a couple of the ML threads, where similar symptoms on manual 4200s were down to the reverse switch. A $25 switch on the gear stick.

Edit: How is your system development progressing? Have you had much feedback since, about, this time last year?

 

[Steve4200]

Yes just a switch if a 4200 manual but if 4200 auto then a bit more complicated.

The EasyMAS system is nearly ready for sale - we will post on forum any update.

 

[Heyes965]

Well ive tested the reverse switch, relays & fuses & all ok, bypassed relay & lights work.
Cleared codes Wednesday & then took the reverse switch box out & checked it & put it back,
Checked codes again & we had P1602 & P1747, but these could be due to taking out switch box,
So cleared codes again today & driven the car for a while & put into reverse a few times with texa linked & we have nothing, live data shows reverse & neutral.
P1602 - permanent supply
P1747 - reverse switch below max threshold

Any ideas & does anyone have a detailed wiring diagram for the reverse lights/ reverse sensor system

Thanks

 

[CatmanV2]

P1602 just means the battery's been disconnected I believe.

Sounds like there's a break between the reverse switch and the ECU, or toasted ECU

C

 

[Navcorr]

What year have you got Heyes956? I've got a "spare" reverse module, albeit left hand drive (don't ask!) but it's from an '02.
As before, the loom connector is different for later modules - '02 as per picture below.
I'm not a million miles away - if you've an '02 you're welcome to try a different module.

 

[Heyes965]

Navcorr
Great!! My is 02 where abouts are you in the country?
Thanks

 

[Heyes965]

Steve 4200

Any further ideas

 

[Heyes965]

Navcorr
They are different part no’s on lhd, one assumes the only differnece is which side the auto switch is on, plug looks the same

 

[Steve4200]

Steve 4200

Any further ideas

What relay did you bypass ?

 

[Heyes965]

Hi steve

Reverse gear relay micro 20a, tested relay ok, reverse lights came on when by passed

Also now notice brake light switch is intermittently working

Any thoughts

 

[Heyes965]

Sorry, one assumes the brake light switch is not on this circuit?