C0255 moderate

Rear Left Active Suspension Solenoid Circuit

The C0255 code means the vehicle's onboard diagnostic system has detected: Rear Left Active Suspension Solenoid Circuit. This is a moderate severity code.

My Garage →
Keep driving?
Short distances only
DIY difficulty
hard
Estimated cost
$300 - $1200 (parts and labor)
Read ABS Codes
BlueDriver Bluetooth Pro Scanner

Basic scanners cannot read ABS codes. BlueDriver reads all systems including ABS, SRS, and transmission through your phone.

Check Price on Amazon

Affiliate link -- we earn a commission at no extra cost to you.

Read ABS Codes
LAUNCH CRP123X (Reads ABS + Chassis)

Basic scanners cannot read ABS codes. This one reads all four systems so you know exactly which sensor failed.

Check Price on Amazon

Affiliate link -- we earn a commission at no extra cost to you.

Common Symptoms

  • Service ride control warning
  • Rear left corner rides harshly or feels loose
  • Vehicle leans to one side over bumps
  • Suspension warning light on
  • Uneven tire wear on rear left

Probable Causes (Ranked by Likelihood)

  • Failed rear left active shock solenoid Very High
  • Corroded connector at rear shock High
  • Wiring damage along rear axle or frame rail Moderate
  • Rear active shock absorber internal failure Moderate
  • Suspension module output driver fault Low

Step-by-Step Diagnostic Procedure

  1. Scan for DTCs and identify the faulting corner

  2. Inspect rear left shock connector for corrosion or damage

  3. Measure solenoid resistance -- compare to factory specification

  4. Check wiring along the frame and rear axle for chafing or breaks

  5. Use a scan tool to command the solenoid and verify response

Frequently Asked Questions

Why does the rear left corner feel different?

When one active shock solenoid fails, that corner reverts to a fixed damping rate while the other three corners continue to adapt. This creates noticeable differences in ride quality and handling balance.

Can a leaking shock cause a solenoid code?

If the shock is leaking fluid significantly, the reduced fluid volume can prevent the solenoid from effectively controlling damping, which may trigger a circuit or performance code.

How long do active shocks typically last?

Active shock absorbers typically last 50,000 to 100,000 miles depending on driving conditions. Rough roads, heavy loads, and extreme temperatures can shorten their lifespan.

Sources

This page is built from documented references. Verify against your own service info before repair work.

Explore More

Was this helpful?

Share carcodefinder.com with a friend who needs to decode their check engine light.