C1705: Rear Speed Sensor Short to Battery
The ABS/ESC module has detected a short to battery voltage (Vbat) in the signal circuit of the left rear center sensor. On Ford applications, this sensor is typically the rear wheel speed sensor (RWSS) mounted on the rear differential (solid axle), which reads the tone ring on the ring gear. A short to positive prevents accurate wheel speed reading, disabling ABS, traction control, and stability control.
1. Commonly Affected Makes
2. Most Common Causes
- Rear wheel speed sensor (RWSS) internally shorted to power
- Sensor wiring chafed or pinched, contacting 12V power wires
- Corroded sensor connector with bent pins or moisture bridging signal to power
- Internal short circuit in the ABS/HCU module
- Improper accessory installation (e.g., trailer hitch) damaging the wiring harness
3. Symptoms You Will Notice
- ABS warning light illuminated
- Traction control and stability control lights on
- Possible loss of ABS, traction control, and stability control functions
4. Step-by-Step Diagnosis
Scan for additional ABS codes and check freeze frame data
Visually inspect the RWSS connector and wiring for damage, corrosion, or contact with power sources
Measure voltage at the sensor signal wire with key on; should not be battery voltage
Test sensor resistance and compare to specifications
If wiring and sensor check out, suspect ABS module internal short
5. Frequently Asked Questions
Is it safe to drive?▼
Yes, but without ABS, traction control, or stability control. Drive cautiously, especially in slippery conditions.
How much does it cost to fix?▼
Typically $150–$400 for sensor replacement, or $200–$600 if wiring repair is needed. Module replacement can exceed $1000.