JDN902

I have 5 codes and they are

P1128(lean condition)

P0141

P0136(o2 sensor which I've had for awhile)

P0455

P0301



I know one of them in an emissions related one and another is multiple misfires....is there any one thing that could cause all of this? I don't know the previous mantience history if the car,so it does need a tune up but yeah.

DTN

Start by fixing the o2 sensor. Then we can weed out the rest of the problems.



A CHECK ENGINE light means FIX ME OR YOUR ENGINE WILL DESTROY ITSELF. It's not "Emissions" It's "I'M RUNNING WRONG!!1!1!!11one!shift+1!!exclamation point!"



Your car tells you when there is a problem. If you don't fix the problem it leads to bigger problems. Your o2 sensor regulates the Air/Fuel mixture as well as ignition timing. When you run with a check engine light you can potentially damage the catalytic converter, the piston rings and the calendars. Not to mention valves and all other systems from backfiring and what not. If you patch over the rough idle you've done nothing.



Start with the o2 sensor, then reset the ECU by disconnecting the negative terminal. The car will now make better decisions because it can regulate it's air/fuel mixture.



It's likely that your car is running funny because there is so much buildup on the spark plugs. So pick them up as well as an o2 sensor. Also, don't skimp out on the o2 sensor, buy a OEM replacement. They're $50-$70 and plugs will run $5 a piece at the dealership max.

majik

I just downloaded an OBD2 Trouble Code Lister for my Android. 1128 isn't on there, but Google had it. Do what DTN said, new O2 and new spark plugs/wires.



P1128 - Air Flow Sensor (maybe?)

P0141 - O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)

P0136 - O2 Sensor Circuit Malfunction (Bank 1 Sensor 2)

P0455 - Evaporative Emission Control System Tank Detected (gross leak)

P0301 - Cylinder 1 Misfire Detected

Stocker

P1128 on my car was a bad O2 sensor intermittently flaking out. There's a troubleshooting matrix for it.

HyundaiKitCoupe

Check leaks on your evap system, including the caniser. I would replace the canister close valve located on the canister itself. if you cannot repair that yourself, i would say go to a good shop and they will perform a smoke test.



you can get evap diagrams from hmaservice.com user:rdtiburon.com password:tiburon



the other codes are your O2 sensors. the sensors might not be bad, but they might be getting bad readings. i am pretty sure that the P0136 is improper voltage going into the sensor, which is why you're getting P0141 with it. i'm not sure what the exact problem could be but i would replace the MAF sensor, possibly the PVC valve connected to the intake manifold, IAC valve in the intake.



it might be a bigger problem. like bad plugs, wires, coils. or it could be the engine misfiring causing all this mess but just go one by one from cheapest fix and work your way up if you are planning on doing this yourself. that way you can be sure to rule out a few things.

majik

I would examine the spark plugs first, and most likely replace. If you haven't changed your wires in 60,000 miles, then go ahead and do that also. Do the regular maintenance items before the other stuff.

DTN

Faults should be corrected before you maintain the car.

majik

^ I was considering them to be a potential contributor to the problem. Yes, faults should be corrected first, but I saw them as a fault and replacing them a potential fix - unless the O2 could trigger a misfire in cylinder 1?

dckeith18

I had misfires in cylinder 1 and it was my TPS

DTN

You do know that each code has it's own value...



The P stands for Powertrain, we will never have B(Body) or C(Chassis) because Hyundai is cheap.



The 2nd digit, 0 stands for standard and 1 stands for manufacturer specific codes.



the third digit....

The fourth and fifth digits narrow it down a bit more to the subtest.