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2011 Chevy Silverado 2WD 5.8L - Fixing C0161 Brake Switch Circuit Fault with ABS and TCS Warning Lights

Model: 2011 Chevy Silverado 2WD Fault Code: C0161 Posted: 2018-01-05 16:05

Hello everyone, I recently had my son-in-law's 2011 Chevrolet Silverado 2WD with a 5.8L engine diagnosed by a friend who scanned the brake system. The scan revealed a C0161 code indicating a brake switch circuit fault. Both ABS and TCS warning lights are illuminated, and the dashboard displays 'Service Traction Control System' and 'Service StabiliTrak'. Most notably, the brake pedal is very stiff—only barely responsive when trying to shift out of park. After investigating, we found a brake light switch located under the dash that connects to the brake pedal. My friend mentioned that twisting this switch slightly while pressing the brake allows the shifter to move freely, similar to how it did when new. This led us to believe the switch was faulty. However, when I consulted a parts store, they explained there are actually three switches under the dash controlling various systems—including traction control and stability functions—and that this particular brake light switch likely only controls brake lights. They questioned why such a switch has five wires and how it could trigger the shifter unlock function if it doesn't directly interface with those systems. Despite their explanation, I’ve seen multiple forum posts suggesting that the brake light switch is still the most probable cause. The part costs $63, which is quite high for a replacement. I’m concerned about spending money on potentially unnecessary repairs—especially since this vehicle will be used daily by my daughter and her family, including for trips with my 3-week-old grandson and 6-year-old granddaughter. Safety matters, but I also want to avoid wasting funds on parts that may not actually be defective. I’d greatly appreciate any expert insight or technical clarification on whether the brake light switch is truly responsible for this issue, especially in a 2011 Chevy Silverado 5.8L with C0161 code and active ABS/TCS warnings.

Related fault codes
C0161
Comments (10)
Anonymous 2018-01-05 22:39

Check bbbind.com for the wiring diagram of the brake switch assembly. Remove the switch and test its contacts for continuity—this will confirm if it's functioning properly. Note that this is not a single switch but an integrated module with multiple functions and more than two wires.

Anonymous 2018-01-05 23:01

Thanks for the tip—I’ll check the wiring diagram first thing in the morning to better understand how the system works.

Anonymous 2018-01-06 05:49

I've reviewed all available wiring diagrams for this model year and vehicle configuration. I don’t see a five-pin brake light switch listed on any official schematics. Could you please share a photo of the switch in question? That would help confirm its design and compatibility.

Anonymous 2018-01-06 20:55

The orange/white and purple wires are part of the brake stop switch, which functions as a simple open-closed switch. This signal is sent to the Body Control Module (BCM), which uses it to communicate with other modules for stability control functions. You can perform voltage checks at the switch to verify whether it's sending proper signals when the pedal is pressed.

Anonymous 2018-01-06 20:59

This issue does not appear to be related to the 5.8L engine—likely a confusion with the 5.3L variant. The C0161 code and brake switch behavior are more commonly associated with the 5.3L models, so this may be an important detail to confirm.

Anonymous 2018-01-06 21:24

The orange/white wire should read 12 volts when the engine is running, regardless of pedal position. The purple wire should only show 12 volts when the brake pedal is fully pressed. This helps determine if the switch is properly activating or failing to activate.

Anonymous 2018-01-06 21:48

I must be honest—I’m not mechanically skilled at all, and my friend doesn’t have the tools to perform voltage tests or diagnostics. I'm just looking for expert opinions on whether the brake light switch is actually the root cause. From what I’ve read in various forums, it seems like a common fix—but I want to avoid spending money on parts that aren't truly faulty. Thank you all for your time and knowledge—your input helps prevent others from being misled by unqualified mechanics or shady repair shops.

Anonymous 2018-01-06 22:18

Opinion: Check Rockauto.com for the correct brake light switch (part number matches GM OEM). It's available under $10 with free shipping. The ACDELCO GM Original Equipment switch is a reliable option and widely used in this model year. If adjusting the switch doesn’t resolve the issue, replacing it is likely the best solution.

Anonymous 2018-01-06 23:02

Thanks so much! I was expecting a recommendation to replace the part, but I didn't anticipate such a cost-effective option. You're definitely a helpful person—I appreciate that. Many thanks, DeWyatt Smith

Anonymous 2018-01-08 23:24

I just wanted to thank everyone for taking time to respond and offer practical advice. To all of you: your willingness to share knowledge freely makes a huge difference—many people would otherwise fall victim to unqualified mechanics or overpriced repairs. I recently purchased a brake light switch based on recommendations, and after my friend installed it, the ABS and TCS warning lights turned off. The dashboard no longer shows 'Service Traction Control' or 'Service StabiliTrak'. Pushing the brake pedal fully now allows the shifter to move freely—just like when new. A big thank you to everyone for your help. DeWyatt (Breadman) Smith