Okay, new guy here, thanks for the space and nice forum as well guys.
Here is the run down. I am a GM technician at a Chevrolet dealership in N/East Ohio and my sister owns a 04' xg350. Last winter she has a problem on the highway when she would accelerate, it would buck and hold back and sometimes stall out. Check engine light came on, I scanned it and I believe it was a p1511 for the Accelator Pedal Position sensor. I followed the flow chart for the code off of Alldata and everything checked out fine, and the circuit was fine as well.

Now, this winter, it is happening like every day. Did a little research online and found there is a TSB for the Accelator Pedal Position sensor, however it shows no diagnosis for the concern, pretty much to just either replace the APP sensor, the TPS sensor or the ECM.

So my question is, before I spend $150 for a APPS which I think is the problem, does anyone know if there another problem out there with these with a different sensor, or if there is a reburn for the ECM for this issue or something?

I would like to see if there is a common problem out there with these if anyone knows here before I take a $150 guess you could say.

Thanks for your time and for the free space!

 

Are you sure you didn't mean a P1151 error code? Most Hyundai engines have a seperate throttle position sensor and air idle controller, but it appears both functions were consolidated to an integrated ETS unit on the XG350. The following provides more definative methods for testing the APS portion of the sensor. Tech info is available on http://www.hmaservice.com/. I hope this helps.

ELECTRONIC THROTTLE SYSTEM (ETS) & ACCEL. POSITION SENSOR (APS)



CIRCUIT DIAGRAM


HARNESS INSPECTION PROCEDURES











SENSOR CHECKING (IDLE SWITCH)[/align]

USING VOLTMETER[/align]

1.Disconnect the APS connector.[/align]

2.Check the continuity between terminal 4 and sensor ground.[/align]

TPS voltage[/align] Continuity[/align]
Higher than 300~900mV[/align] Non-conductive (∞Ω)[/align]
300~900mV[/align] Conductive (0Ω)[/align]

3.If out of specification, replace the throttle position sensor.[/align]

 

Thanks for the detailed information Sir. It appears as if those are same checks I went through last year when this first started hapening if I can recal correctly. Could be the P1151, I knew the numbers but couldnt remember the correct order of them, haha. So it appears as if its either faulty wiring to the APS or a bad TPS sensor, and not a bad APS sensor. Doesnt show anything to actually replace the APS sensor, only the TPS. So, my next question is, is this possibly a common problem of faulty TP sensors on the XG350? Makes sense, could be a bad TPS, but, why the ECM throw a APS malfunction code instead of a TPS code?

 

I was reviewing the two possable error codes:

P1151 = Accelerator Position Sensor (EMS) Circuit
P1511 = ISC Open/Short Coil2 or
P1511 = ISC Circuit Open/Short

Both codes indicate a circuit problem, P1511 indicating a short or open circuit. Both sensors share a common power and common ground lead, but if the harness and both the TPS and APS sensor checks indicate all is OK, I'm not sure what to say. If the fault is in one of the common leads, the error code may simply default to the APS.

 

I am almost positive it was the APS...the DTC that is. I will going over to my sisters house again tonight to scan it to be sure.

 

I have come across this TSB from Hyundai which better explains DTC codes for the electronic throttle system: http://www.hmaservice.com/files/331/.../06-36-003.pdf. I hope it helps.

 

Oh man, thats sweetness there. Thanks. So it appears as it should be a wiring issue, and not the sensor itself. However, what do they refer to as the APS2 sensor? APS1 is the main APS sensor, so would the secondary sensor be the TPS?

Thanks again for the awesome info.

 

To be honest, I was wondering that too. There are only two sensors shown in the previous wiring diagram, so I would assume the TPS is the APS2.

 

That is what I figured as well. I will looking this car over tomorrow on my day off from work. I will let you guys know what I find or if I run into any issues.

Thanks.

 

Before I jump into things tomorrow, do you guys know of any common places for melted or grounded wiring? Any spots where wiring crosses over a hot surface or rubs through or anything out there? I dont think I am going to find a wiring issue however, seeing how this only happens at random, usually at WOT or harder accelleration.