What Does C1751 Mean?
The vehicle speed sensor (VSS) #1 output circuit is shorted to battery voltage (Vbatt). The ECM/ABS module has detected that the VSS output wire is being pulled to system voltage when it should be producing a varying signal proportional to wheel speed. This prevents accurate speed readings and can affect ABS, traction control, and speedometer operation.
Common Causes
35%
Chafed or melted wiring allowing VSS output wire to contact a power wire
25%
Corroded or damaged VSS connector with cross-pin short
25%
Internal failure of the vehicle speed sensor
15%
Short to power inside the ABS/ECM module
Diagnostic Steps
1
Step 1: Disconnect the VSS connector and measure the output pin to ground with a DVOM — if battery voltage is still present, the short is in the vehicle-side harness.
2
Step 2: With the VSS disconnected, check the harness from the module side — measure output circuit for short to battery voltage using the module connector.
3
Step 3: Visually inspect the VSS wiring harness for chafing, heat damage, or contact with positive circuits, especially near the exhaust and transmission.
4
Step 4: If the harness is clean, measure the VSS sensor internally for shorts between its output pin and power pin.
5
Step 5: Repair or replace damaged wiring, clear codes, road test and verify proper speed signal with scan tool live data.
Estimated Repair Cost
$100 - $350
Parts + labor, varies by vehicle and location
The vehicle speed sensor (VSS) #1 output circuit is shorted to battery voltage (Vbatt). The ECM/ABS module has detected that the VSS output wire is being pulled to system voltage when it should be producing a varying signal proportional to wheel speed. This prevents accurate speed readings and can a...
The most common cause of C1751 (Vehicle Speed Sensor # 1 Output Circuit Short to Vbatt) is: Chafed or melted wiring allowing VSS output wire to contact a power wire
Typical repair costs for C1751 range from $100 to $350, depending on the vehicle, location, and whether you do it yourself or go to a shop.
ABS and traction control may be disabled. Speedometer may read incorrectly. Drivable with caution but schedule repair promptly.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1751 to identify the root cause.
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Quick Info
Category
Chassis
System
Vehicle Speed Sensing / ABS System
Difficulty
Type
Manufacturer
Recommended Tools
OBD2 Scanner
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