C1420 ABS Hydraulic Pressure Circuit Short to Battery
The C1420 code indicates a short to battery voltage (Vbatt) in the ABS hydraulic pressure/flow circuit. This Toyota/Lexus-specific code sets when the control module detects an abnormally high voltage signal from the hydraulic pressure sensor or actuator, inconsistent with expected operating conditions. The system continuously monitors circuit integrity to ensure proper electronic brake assist functionality.
1. Commonly Affected Makes
2. Most Common Causes
- Hydraulic pressure sensor wiring shorted to a battery-positive circuit
- Internally damaged hydraulic pressure sensor with an internal short to power
- Corroded or bent pins in the sensor connector causing contact with Vbatt
- Faulty ABS control module with internal signal conditioning circuit failure
- Wiring harness damaged by friction or excessive heat in the engine compartment
3. Symptoms You Will Notice
- ABS warning light illuminated
- Traction control or stability control warning lights on
- Reduced braking performance or loss of ABS function
- Possible limp mode or reduced engine power
4. Step-by-Step Diagnosis
Scan for additional codes and freeze frame data
Visually inspect the hydraulic pressure sensor connector and wiring for damage, corrosion, or shorts
Measure voltage at the sensor signal wire with key on; compare to manufacturer specifications
Check for continuity between sensor signal circuit and battery positive circuits
If wiring and sensor check out, test the ABS module for internal faults
5. Frequently Asked Questions
Is it safe to drive?▼
No, this is a high-severity fault. Driving with a short to battery in the ABS hydraulic circuit can cause unexpected brake behavior or loss of ABS function, increasing the risk of an accident. Have the vehicle towed to a repair shop.
How much does it cost to fix?▼
Repair costs typically range from $200 to $800, depending on the cause. A simple wiring repair may cost $200-$400, while replacing the hydraulic pressure sensor or ABS module can run $500-$800 or more.