Chassis code C0161?

Tiny
WANDERTOAL
  • MEMBER
  • 2009 CHEVROLET SILVERADO
  • 5.3L
  • V8
  • 2WD
  • AUTOMATIC
  • 175,000 MILES
Brake lights on, with key on and headlights selected off brake lights still on as well as third brake light. Lights do extinguish with key off.
Traction control & stabilitrack message illuminate after a few moments of driving. ABS/ brake message not illuminated. Messages reset after key off.
Instrument panel lights will not dim, full bright.
Brake switch has been replaced.
Reseated connector @ the EBCM same condition remains.
Wiring appears to be intact from what I can see.
Can I pull the fuse and disable the EBCM to troubleshoot?
Friday, December 12th, 2025 AT 2:34 PM

5 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,845 POSTS
So, if you pull up on the brake pedal does the lights go off? Also, if you unplug the brake light switch does the brake lights go off? The brake light switch feeds directly into the BCM so if the switch is working correctly the BCM is to blame so I would double check your work on that.

C0161 - ABS / Traction Control Brake Switch Circuit Malfunction

The switch is pretty straight forward, also you might have a defective switch, did it have this problem before changing out the switch? Check out the images (below). Please upload an image or a short video in your response
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Saturday, December 13th, 2025 AT 9:12 AM
Tiny
WANDERTOAL
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I had this problem before replacing the brake switch, cruise control would not engage & the stabilitrack/traction control CAS message would illuminate shortly after driving.
With the brake switch disconnected the brake lights are on, pulling the pedal up, no difference.
Additional codes are B1395-03, B3600-03 & B0081-5A evidently I went in the wrong direction with trouble shooting.
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Saturday, December 13th, 2025 AT 3:20 PM
Tiny
KEN L
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Good job getting the body codes,

B1395-03 - Ignition Accessory Circuit - Voltage Below Threshold
B3600-03 - Security / Key Sense / Column Input - Circuit Low
B0081-5A - Passenger Seat Position Sensor - Incorrect Component / Signal

To me this sounds like the BCM is bad, but lets disconnect the battery and remove the electrical connectors from the BCM and check for corrosion using a flashlight. But we need to make sure the battery in the truck is good which if the engine cranks over you should be okay. Here is the location of the BCM, you can get a rebuilt/programmed unit by searching google or ebay. Check out the images (below). Let us know how it goes
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Monday, December 15th, 2025 AT 10:37 AM
Tiny
WANDERTOAL
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  • 3 POSTS
Ken, quick update. BCM replaced with a pre-programmed from Highway71 auto parts and as of now problem resolved, security light went out first ignition cycle so I didn't go through the relearn.
Reflecting back one morning at work I stepped on the brake and heard "chattering" under the dash (relay?) And never heard that relay click when I stepped on the pedal again. Now I hear the relay make when I step on the pedal.
Thanks far the outstanding troubleshooting!
Will donate soon.
Best to ya, Rick
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Wednesday, January 21st, 2026 AT 3:23 PM
Tiny
KEN L
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Glad you could get it fixed, thanks for letting us know. Please post your new question here, you must be logged in.

https://www.2carpros.com/questions/new

Cheers, Ken
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Friday, January 23rd, 2026 AT 8:42 AM

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