I've got a 2009 Mercury Mariner Hybrid with about 130K miles and several times so far in the last week regenerative braking has faulted out. After turning off the car and starting it back up again everything was fine but concerning, to say the least. My wife mainly drives the car and we have two children so, ya kind of scray and I would love to get some help here.

I ran it through Forscan and I'm getting code C100D-21 "Brake Pedal Angle Sensor Circuit 1" "Signal Amplitude Less Than Minimum"

I've also got a few other codes: U0418 - Invalid Data Received from Brake System Control Module 'A, U2023 - Fault Received from External Node, and Code: C1701 - Rear Outer Left Sensor Fault ( just a back backup sensor that needs replacement)

Does anyone know what's going on here?

It kind of sounds like the brake pedal angle sensor is going out and dropping regenerative braking but I can not find any instructions on how or where this sensor exists.

 

for < $25, you can get 48 hours of access to all Ford manuals:

https://www.motorcraftservice.com/Ho...?returnUrl=%2F

 

I figured I'd follow up here in case anyone on the internet ever gets this code themselves and this forum post pops up. Digging into it I believe the Brake Pedal Angle Sensor has been malfunctioning on my wife Mariner. I contacted my local ford dealership and was given the part number 9M6Z14F385A but was told it was discontinued/obsolete but showed there were 10 in stock at some Ford parts warehouse and they could get it for me for $600. I called fordparts.com to test my luck and they tried to be helpful however they had nothing available. I found one on Fordpartsgiant.com for about $300 but after placing my order it was later canceled as it turns out it was out of stock as well. Nothing was available on eBay or any other parts store. I was about to call my dealership back and shell out $600 but before I did I decided to remove the part first. The sensor is on the far right-hand side of the brake pedal way up under the dash. The screw heads are a Torx Plus 5-point tamper-proof bit size TS20 (I had to use a mirror and my cell phone camera just to see it). Also, it helps to have a mini bit-ratchet to get the screws out since it's a tight spot. After getting it out I tried googling all the numbers on the back and low and behold this same angle sensor was used on a 2010-2013 S400 Mercedes Hybrid. I found a number of brake pedal assemblies on eBay for $130-$200 that had the exact sensor attached to the side. I bought one and it will be here in a few days. After installation, I'll return and report.






This is the back of the part. The plastic retainer will easily fall off FYI.

 

Thanks for following up. Good luck, hope it works.