Long story shortish. I was riding with my wife when our 18 month old started spilling water out of her "spill proof" sippy cup in the back seat. I kind of quickly, and therefore forcefully, leaned back to get the cup before she got it everywhere. When I turned around the passenger seat belt light was flashing, the Air Bag OFF light is on and the SRS light on the dash is on.

I took it to the dealer and they told me that the codes they found were C1231 and B1785. They said I would need to replace the ABS actuator and the steering angle sensor for $3,400 in parts alone. I went and got the car and asked why the SRS light would be on for an ABS problem. They couldn't give me an answer. I got back to the office and looked at the receipt and saw the two codes that were there and called back to ask what the ABS code was. The guy who answered the phone in the service department told me that the tech told him it was in a service bulletin that with those two codes, that is what needs to be changed. I asked him if they had done a zero-point calibration on the occupant sensor and he told me no. I asked how much that would be and he asked me why I would want to waste my money?

The only things I find online about these codes say that the C1231 could be a software problem and there was a service bulletin about updating the software and that the B1785 is one of the force sensors in the occupant sensor that would need to be calibrated. Am I missing something? Does anyone know of a service bulletin involving these two codes that has anything to do with the ABS system?

Thanks in advance. I am tempted to call back and ask what the service bulletin number is but would like to cool off a little before I do.

 

C1231 is steering angle. If the steering angle is reset and the code keeps coming back. There is a service bulletin stating to update the ABS software, TSB-0086-13.

B1785 is the code related to the SRS which is not related to the C1231, steering angle or ABS. The seat occupancy classification sensor or occupancy sensor ECU is bad.

The seat has more the one sensor. It is possible to take the seat apart, find and replace the sensor. Used sensors are available on Epay.

The issue with B1785 is the dealer typically wants to replace the complete seat and not just the sensor. You could by a used seat.

 

That's what I have been reading online. I am going to bring it to a different dealer in the morning and see what they say.

Thanks for confirming what I was thinking.

 

Hi! Were you able to get your vehicle covered for the C1231 ECU item extended warranty through Toyota? I recently encountered the same issue and am about to battle for them to cover the repair. The dealer wants to charge almost $4k for the repair. I also want to gather cases to report to NHTSA.