Diagnostic Trouble Codes (DTCs) showing up while driving can be quite a hassle. What if your car’s odometer gets erratic while driving and starts showing inaccurate speeds? It is an indication that your car has activated the P0502 code. What is that DTC, and how will it affect your car?
P0502 stands for ‘Vehicle Speed Sensor Low Input.’ Your car’s odometer will start functioning erroneously when the code activates. Depending on the car manufacturer, the definition of the code P0502 may vary. Numerous things can cause this; thus, a technician must identify the precise cause in your case to clear the code.
So, what does the P0502 code imply? What are the causes and symptoms of this engine error code? How can you fix it? Continue reading to know all about this diagnostic trouble code!
What does the P0502 code mean?
The code means that the Engine Control Module (ECM) has identified a difference in speed reading between the vehicle speed sensor (VSS) and the wheel speed sensors.
This code covers some models dating back to 1996. First, your car uses a speed sensor to track rotational speed and calculate how fast it moves. Next, they get paired with a toothed reluctor ring wheel or gear, commonly fastened to the differential gear or output shaft of the gearbox or transfer case. Finally, the sensor uses voltage signals to transmit data to the PCM.
The PCM can set off the P0502 code when it notices a low input voltage signal from VSS A. This problem might be mechanical or electrical.
What to do
If you’re driving, wait until you come to a secure stop before pulling over to turn off your engine, check your odometer, and record your current distance. Check to see if any warning lights turn on after confirming this information; if they are, look for issues as soon as possible.
Even if no warning lights illuminate when you first notice a problem, it might be challenging to diagnose some problems before the car has warmed up. So, try to recall how your car was operating before identifying any issues with its speedometer or sensor.
How serious is the P0502 code?
You don’t have to worry if the code shows up. It isn’t a code that causes drivability issues to your car. But, you need to be careful with this code because driving with a faulty odometer can earn you an unnecessary speeding ticket.
Can I drive with the P0502 code?
Yes. It won’t cause any harm to your engine or lead to drivability issues. But try to clear the P0502 code at the earliest, as you may get many speeding tickets due to an erroneous odometer.
What causes a P0502 code?
These are some reasons that could lead to this engine error code.
- A damaged vehicle speed sensor.
- Faulty connectors or wiring in the vehicle speed sensor circuit.
- Defective ABS tone rings.
- A defective powertrain control module (PCM). Because control module failure is uncommon, you must trace the fault before replacing any control modules.
- Improperly sized tires or wheels.
- A malfunctioning instrument panel.
- Excessive metal wear fragments or other material interfere with the speed sensors’ ability to function properly.
What are the symptoms of the P0502 code?
There should be almost no symptoms associated with this issue code, save for a Check Engine Light and an unreliable speedometer. But you may observe these symptoms when the code gets activated in your car.
- The odometer operates inaccurately.
- A difficulty code gets stored and, if possible, one or more lit warning lights, such as the ABS light.
- In some applications, gear shifts may be abrupt, irregular, or unpredictable.
- There may be one or more codes, including transmission, cruise control, traction control, ABS, and stability control system codes.
- Erratic or unexpected activation or deactivation of one or more safety systems may happen on some applications.
- The ABS may deactivate automatically on particular applications and stay deactivated until the code is fixed.
How to diagnose the P0502 code
You can easily find out the source of this code. To determine the cause of the odometer’s malfunction, you’ll need a scan tool to communicate with your car’s ECU. It would be okay to assume a problem with either the VSS or the sensor itself if all connections are secure and there are no broken wires. Next, use an OBD-II scanner to confirm what is causing the error code.
How does a mechanic diagnose code P0502?
A mechanic will perform the following steps to diagnose the code.
- The mechanic would probably begin by locating the vehicle speed sensor since that is the most typical source of the P0502 error code.
- They will then test the vehicle speed sensor using the manufacturer’s suggested protocol to see if the sensors’ wiring and connector appear in excellent condition.
- The mechanic would also confirm the sizes of all the wheels and tires. Finally, they will examine the suspension on all four wheels to inspect the tone rings and wheel speed sensors.
- Suppose the mechanic doesn’t discover any other problems. In that case, the ECM will be examined, and if the customer desires, they will replace the parts.
Common mistakes made while diagnosing the code
The car’s instrument cluster may need replacement if the error code gets stored due to the faulty odometer, which is a common error. Inspecting the instrument cluster at the beginning is crucial because the vehicle speed sensor sends a signal to it.
What repairs can fix the P0502 code?
You can clear the code by performing these repairs.
- Ensuring that the car’s wheels and tires are the appropriate sizes.
- It’s necessary to replace the wheel speed sensor or sensors.
- Replacing a hub bearing.
- Removing and changing the instrument cluster.
- Repairing or changing the connectors and wiring in the circuit that measures the car’s speed.
- Installing a new speed sensor on your car.
- If required, replace the ECM.
Gerard Stevens is an experienced writer specializing in travel and car ownership in the U.S. With over five years in this field, he strives to simplify travel and driving for his readers. Gerard offers valuable guidance on various topics, including car and travel guides, helping his audience feel more confident in navigating these challenges.
