C1512: Right Rear Pressure Reduction Fault
The C1512 code indicates that the Skid Control ECU has detected abnormal performance in the hydraulic pressure reduction function for the right rear wheel during ABS or VSC activation. The ECU monitors actual pressure via internal sensors in the brake actuator and compares it to the target; if the deviation exceeds the calibrated threshold (e.g., the reduction valve fails to open/close properly or responds too slowly), the DTC is stored.
1. Commonly Affected Makes
2. Most Common Causes
- Faulty brake actuator assembly: right rear reduction solenoid valve stuck or leaking internally
- Failing brake actuator pump or pump motor (insufficient base pressure for reduction cycles)
- Air in the right rear hydraulic circuit or contaminated/degraded brake fluid
- Internal failure of the Skid Control ECU
- Wiring or connector between ECU and actuator shorted, open, or with high resistance
3. Symptoms You Will Notice
- ABS or VSC warning light illuminated
- Reduced braking performance or longer stopping distances
- Pulsation or unusual feel in brake pedal during ABS activation
- Vehicle may pull to one side during hard braking
4. Step-by-Step Diagnosis
Scan for all stored codes and freeze frame data; verify C1512 is current.
Inspect brake fluid level and condition; bleed right rear brake circuit to remove air.
Test brake actuator pump and motor operation using a scan tool.
Check wiring and connectors between Skid Control ECU and brake actuator for damage or corrosion.
Perform actuator solenoid test with a scan tool to verify right rear reduction valve operation.
If all else passes, replace the brake actuator assembly or Skid Control ECU as per manufacturer procedure.
5. Frequently Asked Questions
Is it safe to drive?▼
No, driving with this code is not recommended. The ABS and VSC systems may not function properly, increasing the risk of loss of control during emergency braking or slippery conditions.
How much does it cost to fix?▼
Repair costs typically range from $200 to $1,200 USD, depending on the root cause. A simple brake fluid bleed may cost $100-$200, while replacing the brake actuator assembly can run $800-$1,200 including labor.