Check Engine Light After Installing SMI Air Force One Supplemental Braking System

Updated 10/14/2019 | Published 10/12/2019

Products Featured in This Question

Demco Air Force One Flat Tow Brake System for RVs w/ Air Brakes - Proportional

(543)

$1399.00

Roadmaster Stop Light Switch Kit

(671)

$42.66

Question:

2014 Mini Cooper S hatchback, system installed and appears to be functioning properly when tested. however, when running the car the check engine light now comes on. My guess is that there maybe a vacuum issue from adding the T to the Vacuum booster line I added the check valve as instruction stated. That modification was the only thing that could cause the light. I cant hear a leak but doesnt mean its not there.

asked by: Rick S

Helpful Expert Reply:

If a check engine light appears after installing the SMI Air Force One Supplemental Braking System part # SM99243 you could either have a leak as you mentioned in the vacuum system, the check valve which is tied into the vacuum system is installed backward, or there was an issue with the stop light switch connection. If you were to have the code pulled by taking the vehicle to a local auto parts store I would be able to narrow down which of theses issues has occurred.

For starters, the stop light circuit on a 2014 Mini Cooper should not be spliced into directly but instead obtained with the Roadmaster Stop Light Switch Kit part # RM-751469. If you are already using a stop light switch then check to make sure you have the check valve originated correctly. The black end of the check valve will need to be installed so that the line attached to it leads to the motor. The green/clear end of the check valve will need to be installed so that the line attached to it leads to the booster. If this is correct then next step is to feel all the fittings to see if air is escaping but there is a smoke machine used in repairs shops that can detect this as well. If your cruise control does not work then you have a vacuum issue.

expert reply by: Conner L