P0456, C1503, and Some Symptoms 2015 Elantra

Hello,

For maybe 3 months, I’ve had P0456 come on and off. Zero symptoms, just a code. It seems to come on when I occasionally spike the rpms, and seems to turn off after many miles of not spiking rpms.

For about a month, I’ve experienced a few symptoms:
2-3 times the car wouldn’t start upon first key turn. Started right up like new on 2nd key turn. On the first key turn, there was cranking for about 3/4 of a second, which is about how long it takes for the engine to start normally, and then the cranking stopped even though I didn’t unturn the key.
2 weeks ago I shot the rpms to maybe 6k pulling out of my neighborhood, oil warm but not hot, and my engine shut off. I pulled over, checked my oil, started her up like new. CE light wasn’t on.

Now back to codes:
Yesterday the solid yellow CE light came on again. Auto Zone scanner shows C1503 in addition to P0456.

Does anybody know what’s going on?

P0456 - EVAP system has detected a leak. Could be caused by the fuel cap leaking. This was common on Santa Fe.

Can you smell fuel fumes?

C1503 - ESP issue. Not a common issue I’ve come across in the past. Have you got the ESP light on?

@Joy
I’ve replaced the gas cap twice. The 2nd was from the dealership. I cleaned the opening. There are no leak symptoms, no smell, no loss in mpg.

I should add, I’ve babied this thing since I got her. I pretty much always run low rpms. I’ve maintained the car appropriately. I’m extremely sensitive with the car on inclines. I’ll go 55 up a steep hill while others go 65-70, because I want my car to live!
Fuel pump is fairly new, battery is clearly not the problem and is 2.5 years old but most expensive battery, Spark plugs and ignition coils are new.

It seems like electrical problems, but I don’t know for sure nor specifically what electrical problems. Wiring, sensors, modules, I don’t know. Relays all look brand new.

C1503 could be one of your speed sensors.

P0456 indicates a small leak in a vehicle’s evaporative emission control (EVAP) system; it could be as simple as the gas cap.

StellarisSeeker said:
C1503 could be one of your speed sensors.

P0456 indicates a small leak in a vehicle’s evaporative emission control (EVAP) system; it could be as simple as the gas cap.

I’ve replaced the gas cap twice, and cleaned the opening. The 2nd gas cap is from the dealership. There are no leak symptoms. No smell, no loss in mpg since I bought the car.

StellarisSeeker said:
C1503 could be one of your speed sensors.

P0456 indicates a small leak in a vehicle’s evaporative emission control (EVAP) system; it could be as simple as the gas cap.

I’m thinking there is some sort of overarching electrical problem, but I really don’t know.

Google the codes.

Victor0 said:
Google the codes.

I have, but I think my problem is something bigger or more tricky than just what the codes say individually. Or it’s electrical.

You need an evaporative leak test. It’s done with smoke to find leaking fuel vapors. Pulling the code will only tell you you have a leak in the system, not what you need replaced.

Auto said:
You need an evaporative leak test. It’s done with smoke to find leaking fuel vapors. Pulling the code will only tell you you have a leak in the system, not what you need replaced.

I actually have a smoke machine, but I haven’t used it, because there doesn’t seem to be a leak. I guess I should try it.

@Austin
Could also be an O2 sensor causing both codes.

Auto said:
@Austin
Could also be an O2 sensor causing both codes.

Really? That’s common?