Q: CEL lights p0501 p0500 p1529 u1400 on 2001 Hyundai Elantra

asked by on May 25, 2017

My car get's the codes, p0501,p1529,p0500,u1400 and has trouble shifting down after acceleration as well as taking off from a full stop, runs on a very low idle (less than 500RPM). Gets terrible gas millage at about 18 MPG

My car has 188000 miles.
My car has an automatic transmission.

Codes P0500, P0501, and P1529 are related to vehicle speed sensor input. The engine control unit relies on sensor input from the wheels and transmission - as well as dozens of other sensors - to determine how fast the vehicle is going. If the check engine light is on with these codes present, the ecu will put the vehicle into sort of a "limp mode" where it will run, but not run correctly. Possible causes could be a wheel speed sensor which also provides input for the anti-lock braking system if equipped (most commonly at the right front wheel), or the vehicle speed sensor which is typically located on or in the transmission. Code P1400 is related to exhaust gas recirculation (egr). Through the egr valve a small amount of burned air and fuel is rerouted from the exhaust and back into the combustion chambers at certain speeds to cool the combustion chambers and reduce the chances for ’knock and ping". Although unrelated to vehicle speed, this code may simply be present due to the way the engine is running due to the speed codes. Have a certified technician inspect the vehicle. If replacement of a wheel or vehicle speed sensor is determined to be the cause and replaced, the egr code may go away. If it returns, then the egr system will have to be inspected to find the exact cause for that code.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing


Experienced Mechanic?

Earn up to $65/hr

What others are asking

Truck cuts off when stopping

Hello. Stalling at stops can be caused by many things. A few common causes are: faulty idle air control valve vacuum leak fuel or engine management issue The most common of these is a failed idle air...

Hesitation and smoke

Hello, thank you for writing in. While it is typical for the engine to give off some white smoke upon starting (as it burns condensation that builds while off at night), what you describe sounds more like a coolant leak....

the truck turns over and over, but will not start

If the starter motor is turning the engine over rapidly, at sufficient RPM, but the engine does not catch and run, that means that there is an ignition, fuel, air induction, or mechanical fault in the engine that will have...

Check Engine Light and air conditioning problems

The Check Engine Light illumination is most likely due to your engine having a misfire, and also getting a code to the cam sensor. If the misfire code is pointing to a particular cylinder misfiring, there could be another problem...

Overdrive not working.

It sounds like you are having an electrical problem that is affecting several systems. These can be tricky to diagnose. Sometimes they can be tied together and fixed with a single repair or several different repairs may need to be...

Ignition not turning.

This is a common problem with the Ford Focus. Most likely, the ignition cylinder is bad and requires replacement. A certified technician, like one from YourMechanic, will be able to repair this for you.

Vehicle makes whistling noise when warm

A vacuum leak is a possibility but another possibility would be an exhaust leak. Both can cause a whistling noise when the engine heats up. A vacuum leak is more likely to change with engine speed. A qualified technician, like...

Find TDC and also set cam position sensors.

Hi there. If you are just replacing the camshaft sensor then all you need to do is unbolt the sensor and install the new sensor. If you are installing a new oil pump driver under cam sensor then remove number...

I am installing a timing belt on a crate motor. The intake side camshaft tdc marks do not line up perfectly like the exhaust side

Hello. If there was not a timing belt on the engine already then you need to be careful about turning everything. As long as you are taking it easy and being vigilant of any binding you can turn each of...

Related articles

A Buyer’s Guide to the 2012 Hyundai Tucson
The The 2012 Hyundai Tucson is available in front wheel drive and all-wheel drive. It has a distinguish look that is both stylish and elegant For 2012, the Tucson was named the second best compact SUV available on the market,...
The Best Used Cars to Buy for Teenagers
If If you’ve decided that you’re ready to purchase a used car for your teenager, then you’re probably pretty picky about what you’re looking for. Likely affordability, safety, and fuel economy are high on the list. With that said we’ve...
How to Replace the Oil Temperature Sensor on Most Cars
Oil, as well as the oil temperature sensor, is crucial to the engine lubrication system. A bad sensor can lead to leaks and poor vehicle performance.