What Does P0500 Mean?
The vehicle speed sensor (VSS) circuit is not providing a valid signal to the ECM/PCM. Note: While some databases label this as a cooling fan code, P0500 is the standard OBD-II code for Vehicle Speed Sensor 'A' malfunction. The ECM is not receiving vehicle speed data, which affects transmission shift points, speedometer operation, cruise control, ABS, and torque converter lockup. The driver will likely notice a non-functional speedometer, erratic shifting, and disabled cruise control.
Common Causes
30%
Vehicle speed sensor failure (internal circuit open or short)
25%
Damaged or broken wiring between the VSS and ECM/TCM
20%
Corroded or loose connector at the vehicle speed sensor
15%
Damaged reluctor ring/tone wheel on the transmission output shaft or differential
10%
ECM/TCM internal speed signal input circuit fault
Diagnostic Steps
1
Monitor vehicle speed PID in live data while driving at a steady 25-30 mph. If the reading is 0 mph or erratic, the fault is confirmed. Compare with a GPS speedometer app for reference.
2
Locate the vehicle speed sensor (typically on the transmission tailhousing or transfer case). Inspect the connector for corrosion, damage, or loose fit. Check the sensor for physical damage or contamination.
3
Measure the sensor output: For a magnetic pickup type, check AC voltage output while spinning the input shaft (should produce 0.5-2.0V AC). For a Hall-effect type, verify 5V reference, ground, and a square wave signal output.
4
If the sensor tests good, check the wiring from the sensor to the ECM/TCM for continuity and shorts. Pay attention to areas where the harness routes under the vehicle and is exposed to road debris, water, and corrosion.
5
Inspect the reluctor ring on the output shaft (visible when the sensor is removed). Look for missing teeth, cracks, or debris packed between the teeth that could prevent proper signal generation.
Estimated Repair Cost
$50 - $400
Parts + labor, varies by vehicle and location
The vehicle speed sensor (VSS) circuit is not providing a valid signal to the ECM/PCM. Note: While some databases label this as a cooling fan code, P0500 is the standard OBD-II code for Vehicle Speed Sensor 'A' malfunction. The ECM is not receiving vehicle speed data, which affects transmission shif...
The most common cause of P0500 (Cooling Fan Power/Ground Circuit Malfunction) is: Vehicle speed sensor failure (internal circuit open or short)
Typical repair costs for P0500 range from $50 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Drivable but with significant impacts: the speedometer may not work, transmission may not shift correctly (harsh shifts or stuck in one gear), cruise control will be disabled, and ABS/traction control may be affected. Drive cautiously and avoid highways where accurate speed information is critical. Repair soon.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0500 to identify the root cause.
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Quick Info
Category
Powertrain
System
Vehicle Speed / Transmission Control
Difficulty
Type
Generic (SAE)
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