Code p0502 - Cadillac Cars & Trucks

Bad bearings mine bad sensors, broken ABS wires,

Vehicle Speed Sensor (VSS) circuit low input.

Check out this link
P0502 Saturn Vehicle Speed Sensor Circuit Low Input

This is what I found for the code. P0502

does code p0502 mean my transmission is bad on a 1997 cadillac deville

That is a speed sensor "a" low input code. Sometimes the sensors are external and sometimes they are internal. I don't remember specifically for your vehicle.

I would suggest monitoring the sensor with a higher end scan tool capable of reading transmission data.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

P0302Cylinder 2 Misfire Detected for the P0502 click on this site or plug it into your address bar.
http://engine-codes.com/P0502.html

P0502 is a Vehicle speed sensor issue:
P0502 Description The vehicle speed sensor outputs a 4 pulse signal for every revolution of the rotor shaft, which is rotated by the transmission output shaft via the driven gear. After this signal is converted into a more precise rectangular waveform by the waveform shaping circuit inside the combination meter, it is then transmitted to the ECM. The ECM determines the vehicle speed based on the frequency of these pulse signals.

Symptoms - Engine Light ON (or Service Engine Soon Warning Light)
- Speedometer may not work properly
- Transmission shifting problem Possible Causes - Vehicle speed sensor harness or connectors is open or shorted
- Vehicle speed sensor
- Combination meter
- Faulty ECM.

P0502 Vehicle Speed Sensor "A" Circuit Low Input

Change the speed sensor or check the wiring to it.

The Code you're referring to should be a "P0502." What the Code signifies is: "Vehicle speed sensor circuit, low input."

P0404 Exhaust Gas Recirculation Circuit Range/Performance
P0502 Vehicle Speed Sensor Low Input
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hope that helps /a little beyond my expertise but theres your codes your looking for ;)