C1255 — ABS Inlet Valve Coil RR Circuit Open #

The code label may vary depending on the vehicle manufacturer.

Known label variations:

• ABS Inlet Valve Coil RR Circuit Malfunction (Toyota)
• Right Rear ABS Inlet Valve Circuit Open (Ford)
• ABS Valve Coil Circuit Open, Rear Right (GM/Chevrolet)
• RR ABS Inlet Valve Circuit Open (Hyundai/Kia)

Code Summary for C1255 #

The C1255 diagnostic trouble code (DTC) is triggered when the Anti-lock Braking System (ABS) module detects an open circuit or electrical issue in the right rear (RR) inlet valve coil. The ABS is a safety system that prevents wheel lockup during braking by modulating brake pressure. The inlet valve controls the flow of brake fluid into the wheel cylinder, and the coil is the electrical component that actuates this valve. An open circuit means the electrical pathway is interrupted, preventing the valve from operating properly. This code typically means the ABS cannot properly control brake pressure to the right rear wheel, potentially impacting braking performance.

Common Symptoms for Code C1255 #

Drivers experiencing C1255 may notice changes in how their vehicle responds during braking, especially in situations where ABS would normally engage. The ABS warning light is usually illuminated on the dashboard, signaling a fault in the system. In some cases, the vehicle may revert to standard braking mode, disabling advanced safety functions. Other symptoms can be subtle or intermittent, depending on the nature of the electrical fault.

• ABS warning light on
• Loss of ABS function (brakes operate normally, but without ABS modulation)
• Increased risk of wheel lockup during hard braking or slippery conditions
• Possible traction or stability control warning lights
• Intermittent or persistent warning chimes

Probable Causes for Code C1255 #

The most frequent causes of a C1255 code are related to electrical issues affecting the ABS system, specifically the right rear inlet valve coil. These issues can range from simple connection problems to component failures. Understanding the order of likelihood can help prioritize your diagnosis and repairs.

1. Damaged or corroded wiring/connectors to the right rear ABS inlet valve coil
2. Failed right rear ABS inlet valve coil (actuator solenoid itself)
3. Open circuit or high resistance in the ABS wiring harness
4. Faulty ABS control module (less common, but possible)
5. Poor ground connection near the affected ABS sensor or module
6. Aftermarket modifications interfering with ABS circuits

Step-by-Step Diagnostic for Code C1255 #

Diagnosing C1255 requires a methodical approach, starting with the simplest and most common problems before considering component replacement. Always ensure the vehicle is safely parked and the ignition is off before working on the braking system.

• Check for additional ABS or brake-related codes using a scan tool—these can provide more context.
• Visually inspect the right rear wheel area for obvious signs of damaged, pinched, or corroded wiring and connectors leading to the ABS inlet valve.
• Disconnect the electrical connector from the right rear ABS inlet valve coil. Inspect for bent, backed-out, or corroded pins.
• Use a digital multimeter to check continuity and resistance in the coil circuit. Compare readings to OEM specifications.
• Test voltage at the connector with the ignition on (refer to wiring diagram for expected values).
• If wiring and voltage are correct, use the scan tool’s active test function (if available) to command the valve and observe response.
• If the valve does not respond, suspect a faulty coil or actuator. If all else checks out, consider ABS control module malfunction.

Possible Repairs for Code C1255 #

Repairs should always address the root cause of the C1255 code. Random parts replacement is not recommended. Use only OEM or high-quality parts to maintain ABS reliability and safety.

• Repair or replace damaged wiring or connectors to the right rear ABS inlet valve coil
• Replace the right rear ABS inlet valve coil (may be part of the hydraulic modulator unit)
• Repair poor ground connections in the affected ABS circuit
• Replace the ABS control module (only after confirming all other components are functional)
• Remove or correct any aftermarket modifications interfering with ABS wiring

Is It Safe to Drive with Code C1255? #

Driving with code C1255 is possible, but not recommended. While the vehicle’s basic braking will remain operational, you will lose ABS function on at least one wheel, increasing the risk of wheel lockup and loss of control during emergency stops or on slippery roads. The ABS and possibly traction or stability control warning lights will remain illuminated. For your safety—and the safety of others—it’s best to have the issue diagnosed and repaired as soon as possible.

Vehicles Most Affected by Code C1255 #

C1255 is a manufacturer-specific code most commonly found in vehicles equipped with advanced ABS systems. While it can appear in a wide range of makes and models, certain vehicles and brands see it more frequently, especially those using similar ABS module designs.

• Toyota (Camry, Corolla, Tacoma, Highlander, etc.)
• Ford (F-150, Escape, Explorer, Fusion, etc.)
• Chevrolet (Silverado, Malibu, Equinox, etc.)
• Hyundai/Kia (Sonata, Elantra, Santa Fe, Sorento, etc.)
• General Motors SUVs and trucks

Common Mistakes & Best Practices for Code C1255 #

Misdiagnosis of C1255 can lead to unnecessary parts replacement and wasted time. Following best practices can help you fix the problem efficiently and avoid common pitfalls.

• Overlooking simple wiring issues—always inspect connectors and grounds before replacing expensive parts.
• Replacing the ABS control module without confirming the actuator or wiring is actually at fault.
• Ignoring related codes that could provide further clues about the failure.
• Failing to clear codes after repairs and confirming the fix with a test drive.
• Using non-OEM components that may not meet quality standards for ABS systems.

Quick FAQ for C1255 #

Still have questions about the C1255 code? Here are some rapid answers to the most common concerns:

Q: Will my brakes stop working if I have C1255?
A: No, your basic brakes will still operate, but you will lose ABS function on the affected wheel, increasing the risk of wheel lockup under hard braking.

Q: Can I reset the code by disconnecting the battery?
A: While disconnecting the battery may temporarily clear the code, the underlying fault will cause the code and warning light to return until the issue is properly repaired.

Q: Is this likely to be an expensive repair?
A: Costs vary widely—simple wiring repairs are usually affordable, but replacing the ABS actuator or module can be more costly. Accurate diagnosis is essential to avoid unnecessary expenses.