P0501 code definition
Vehicle Speed Sensor Range/Performance
What the P0501 code means
P0501 is an OBD-II generic code that the engine control module (ECM) got an input from the vehicle speed sensor (VSS) that is out of range or an erratic voltage output that is not stable or smooth, with movement up or down.
What causes the P0501 code?
The VSS output voltage jumps up or down faster than the ECM expected causing the ECM to determine the VSS is out of specification range for performance.
The VSS voltage output is lower than expected causing a lower than normal speed output compared to actual vehicle speed.
What are the symptoms of the P0501 code?
The Check Engine Light will be illuminated and the code is set in ECM memory.
The transmission shifting may be too fast or too slow depending on VSS signal output is too low or too high.
The speedometer will not act normal and may jump up and down or may read low or high compared to road speed.
The engine may seem to be low on power due to transmission erratic shifting.
How does a mechanic diagnose the P0501 code?
Scans codes and documents the code in the ECM
Monitors the VSS signal while driving at known speeds using a GPS signal or another vehicle and see if the speedometer is accurate within a few miles per hour
Checks the VSS electrical connection for loose or corroded connections
Removes the VSS and looks at the tip of sensor for metal particles causing the weak signal, cleans and retests for proper operation
Common mistakes when diagnosing the P0501 code
Not verifying that the output is bad from the old sensor before replacing the VSS
Not removing and checking the VSS for excessive metal particles, indicating a problem with internal transaxle or rear axle components
How serious is the P0501 code?
Code P0501 is an indication that the VSS is not working correctly and it can cause transmission damage and erratic shifting.
The Check Engine Light being on causes the vehicle to fail emission testing.
The rear end type VSS will cause the ABS light to be on and the ABS to be disabled.
What repairs can fix the P0501 code?
- Replacing the VSS in the transmission or rear end
- Repairing the wire connection to the VSS
- Cleaning off metal particles, clearing the codes, and performing a road test
Additional comments for consideration regarding the P0501 code
Code P0501 is for vehicle speed input to the ECM for the anti-lock brakes and transmission input for vehicle speed. The VSS can cause problems in multiple systems that use its input.
Need help with a P0501 code?
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