I am having a DSC system fault which my code reader indicates is a C1186 - failsafe relay stuck open. Does anyone have any experience debugging this code? Search did not turn up anything.

 

Solution to the problem appears to be replacing the DSC module.

However, local dealerships are unable to make a used module authenticate to the powertrain ECU. I am being told only a new ($1400) module can be mated to the car. Can anyone confirm?

 

If your dealership gives trouble recoding a DSC module as mine did, ask them to call the Mazda techline. Master tech and service manager refused to believe it was possible to recode a used module. Tech line walked them through it without issue.

 

I have the same fault code, do you have the part number for the module? Or a picture of how it looks like?
Did this fix your problem permanent?

 

There isn't a separate part number for the electronics module. Mazda wants you to buy it in an assembly which includes the hydraulic block. A new module with the hydraulic block lists somewhere around $3500 for DSC or $1500 for ABS.

I was able to get a used module without hydraulic block on ebay for about $100. Don't buy one with the hydraulic block attached- I did this twice and both times had to seek a refund as the solenoids on the module were rusted and seized. The solenoids should be shiny and move readily if you gently push them - not too hard or they will break.

Recoding the module cost another $100 or so - basically one hour of labor from the dealership. Had to show up to two appointments, first time they claimed the recoding wasn't possible and did a hard sales pitch on a new module. Second time they actually tried and it recoded with no issue per directions of the Mazda Techline.

Have been driving it for about 5-6 months now without further issue.

 

holy crap that is expensive, I found a crashed Rx8 from a dealer nearby so I will ask to see if i can get the unit cheap.
Good to hear it worked out for you and thanx for the useful information :D
Did you try to connect the unit without recoding it first? I wonder if i will be able to see if the fault code dissappers before I take to the dealer. But there will probably not be any communication at all if I do?

 

you can recode a used one.

tell them to grab As-built data from the Search Engine and start from there, don't follow exactly what IDS saids, just do it like you're installing a new module.

I'm so shocked that so called "mazda factory trained" tech couldn't figure this out on their own, I did it without any "help" from any tech line whatsoever.

 

thats interesting, I need to check if I got 12v(b+) on pin O on the ABS/DSU wire harness before I go to the next step

 

No luck, I need to replace my unit also.
I talked to the dealer and they want 6381$ (38000NOK) for a new unit, wonder why its about the double price here in norway thats insane!
But Im getting a used one from ebay for around 100$ with shipping :D

 

Got the new unit, installed it and now i only got the mismatch fault code*which is good and what I expected :D Thanx :-)