OBD-II Diagnostic Trouble Code
C0277 — Brake Pedal Position Switch Circuit
C0277 indicates a fault in the brake pedal position switch circuit. The brake module saw a switch signal that is open, shorted or not consistent with other brake data, such as the switch showing applied with no deceleration. Some OEMs use this code for a brake pedal position sensor rather than a switch.
Severity 3/5
Truck-relevant
Service this week
Severity
Service this week
Brake Pedal Position Switch Circuit
Code
C0277
Category
Chassis
Subsystem
Brakes
Truck-relevant
Yes
What this means for truckers
C0277 (Brake Pedal Position Switch) — pedal position fault.
Before you replace parts — try this first
C0277 on the Brakes system is most often misadjusted or failed brake pedal switch — not a dead part. On commercial diesels especially, work these in order before spending money on parts:
- Confirm the symptoms. Match what your truck is doing to the Symptoms section below. If the code is set but the symptoms are not there, clear the code and re-test after a drive cycle — it may not return.
- Clean and dry the sensor connector. Water, road salt, or oil seeping into a connector is the #1 fake sensor failure. Disconnect, look for green corrosion or moisture, spray with electrical contact cleaner, dry, reseat. Many faults clear here for $0.
- Inspect the wiring harness. Trace the wire from the sensor toward the ECM — look for chafing against the engine block, melted insulation near the turbo or exhaust, or pinch points where a clamp has rubbed through.
- Test the sensor before swapping it. Most Common Causes (below) list the expected voltage or resistance range — a $20 multimeter saves a $300 sensor swap that does not fix the problem.
- Only then, replace the part. Use the OEM or a tier-1 aftermarket. Cheap sensors throw the same code in two weeks.
Symptoms
ABS, traction or stability lights on, cruise control may not work, and brake lights may not work or stay on. On automatic trucks with a brake-shift interlock, the shifter may not come out of park. Base braking is normal.
Common causes
- CommonMisadjusted or failed brake pedal switch ($40–$200)
- OccasionalWiring or connector fault at the pedal ($80–$300)
- OccasionalBlown fuse in the switch feed ($10–$80)
- RareModule input failure ($600–$2000)
How to fix
Check brake lights and fuse
When to use: First quick check
Watch brake switch status on a scan tool while pressing the pedal
When to use: Confirm switch operation
Adjust or replace the switch
When to use: Switch is erratic or stuck
Repair wiring between switch and module
When to use: Switch is good but signal is lost
Affects most
No specific vehicle pattern found in our complaint database. This code can appear on any vehicle that supports OBD-II diagnostics.
Related
- → Browse all DTC trouble codes
- → Decode a VIN to check codes for your truck
- → Owner-operator maintenance guides
- → C0235 — Vehicle Speed Sensor Circuit
- → C0237 — Vehicle Speed Sensor (drive train)
- → C0249 — Brake Boost Sensor Out of Range
- → C0265 — EBCM Relay Circuit
- → C0282 — Brake Pedal Travel Sensor Circuit
Frequently Asked Questions
Can I drive with code C0277?
C0277 is severity 3 — plan service within a few days. Performance is likely degraded already (you may feel reduced power, harsher shifts, or slightly worse fuel economy). Continuing to drive risks additional damage to adjacent components.
How much does it cost to fix C0277 on a commercial truck?
Total repair cost ranges $10–$2000 depending on the root cause. The cheapest fix is usually the first one listed below — Misadjusted or failed brake pedal switch — which is also the most common. On commercial trucks the cost is usually higher than passenger vehicles due to part availability and shop labor rates ($120–185/hour at most truck shops, vs $90–130 at general auto shops). DIY-capable fixes (sensors, hoses, filters) are at the low end; major component replacements (turbo actuator, high-pressure fuel pump, transmission solenoid pack) are at the high end. Always diagnose with a scan tool BEFORE replacing parts — guessing wrong on a $1,500 turbo actuator when the actual issue was a $30 boost hose is a common expensive mistake.
Will C0277 fail a DOT inspection?
C0277 is generally not a direct DOT inspection fail item by itself. Inspectors focus on safety-critical systems (brakes, steering, tires, lights, hours-of-service). However, the check engine light alone can trigger additional inspection scrutiny. Best practice: fix the code and clear it before a planned inspection.
What's the difference between C0277 and related codes?
C0277 is closely related to: C0235 (Vehicle Speed Sensor Circuit), C0237 (Vehicle Speed Sensor (drive train)), C0249 (Brake Boost Sensor Out of Range), C0265 (EBCM Relay Circuit). These codes share the same subsystem (brakes) and often appear together. If you see this code, scan for the full code list — fixing the root cause usually clears multiple companion codes at once. If only C0277 is set without the companions, the issue is more isolated.
How do I prevent C0277 from coming back after a repair?
For C0277 (Brake Pedal Position Switch Circuit), prevention centers on the brakes system. Clean wheel speed sensors at every brake service. Inspect tone rings for cracks or rust. Keep ABS sensor harnesses away from chafe points. Don't drive through deep water that can flood the rear wheel-speed sensor connectors.