C1505: Left Rear Solenoid Valve Circuit Fault
The C1505 code indicates that the Skid Control ECU has detected an electrical or mechanical failure in the left rear solenoid valve circuit within the brake actuator assembly. This can be an open circuit, short to ground, short to battery, or a mechanically stuck valve, preventing proper hydraulic pressure modulation at the left rear wheel during VSC/ABS activation.
1. Commonly Affected Makes
2. Most Common Causes
- Faulty brake actuator assembly (left rear solenoid valve shorted or open)
- Damaged, corroded, or loose wiring or connector at the brake actuator
- Defective Skid Control ECU
- Low battery voltage or power supply circuit fault (fuse, relay) to the actuator
3. Symptoms You Will Notice
- ABS, VSC, and/or brake warning lights illuminated
- Reduced braking performance or abnormal brake pedal feel
- Loss of stability control or ABS function
4. Step-by-Step Diagnosis
Scan for all codes and check freeze frame data
Inspect brake actuator wiring and connector for damage, corrosion, or looseness
Test battery voltage and check related fuses and relays
Perform actuator solenoid resistance and continuity tests per service manual
If wiring and power supply are OK, replace the brake actuator assembly
After repair, clear codes and test drive to verify system operation
5. Frequently Asked Questions
Is it safe to drive?▼
No, driving with this code is not recommended. The vehicle may lose ABS and stability control, increasing the risk of skidding or loss of control during emergency braking or slippery conditions.
How much does it cost to fix?▼
Repair costs typically range from $300 to $1,200, depending on the root cause. A brake actuator replacement can cost $500–$1,000 plus labor, while wiring repairs may be less.