The p0102 DTC
 

I've gone through some of the threads regarding this somewhat mysterious cause of engine hesitation and buckling courtesy of the P0102, the car acts up when the engine is fully warmed up and during stop and go driving..but it drives okay on WOT, engine also keeps running without stalling with the MAF connector removed



but most have been fruitless in terms of fixing the problem, especially part swapping. I have a ultra gauge that shows real time data from the ecu and it's showing me abnormal engine load and MAF G/S readings..



the engine without a/c and idle had a calculated engine load of 2.75%, now it's at 1.18%



MAF G/S "Grams per second" was around "3.7" now it's at less that "2" it also fails to register around 10-13 G/S at 3000RPM which is the norm







The engine light does not come on but it shows up under pending codes..



I've checked the wires, plugs, IAC, IAT, coolant sensor, coolant sender, gone through 3 good MAF sensors, checked and replaced bad downstream sensor due to irregular voltage readings, catalytic converter" "substrate had a hole punched in it"

retorqued the intake manifold nuts to factory spec, changed brake booster hose, checked hoses on Evap canister, replaced CCV valve, cleaned 2 way valve, checked purge solenoid valve, cleaned all visible grounding points..



after endless troubleshooting..i narrowed down the problem to the possible fact that the green wire at the MAF connector isn't showing the 5 volt signal reading from the ECU, the "blue/white" sensor ground from the ecu is okay, "red/white" 12V feed power from the battery is okay, "BLACK" Body Ground is okay





has anyone replaced their ECU's due to possible electric shorts from the ECU?

You should have the full 5v when the key is on and the connector unplugged.



What;s the resistance of that wire back to the ECU with the key off?

Check the MAF, check the wires, then replace ECM.





http://imageshack.us/a/img600/986/78420422.gif

What my Voltmeter is telling me with volts on DC..red probe on power and black probe on negative battery terminal, vice versa for ground testing



T-pin slipped into terminal connector



black wire..12 volts..good ground

red/white wire.. 12 volts..good 12v batt power

blue-white wire..good sensor ground of 12 volts

green wire..5 volts..rises and drops smoothly with gradually revving of engine



so the MAF registers okay, the wiring seems okay..has good continuity on all 4 wires, gentleman..are we looking at a bad ECU?

According to MotorAlldata... yes. No other sensors or emissions components cause a MAF sensor code.

well guess what? the ECU wasn't the fault..went to the junkyard pulled a ECU off a 1997 J2 wagon and the car started right up with the same parameters..low MAF reading of less than 2.00g/s at idle and low engine calculated load of 1.18%..should be 2.75% at idle of 800rpm.



for the tumultuous month i been having doing shotgun troubleshooting and throwing parts and money from cheap to pricey .."scannerdanner" would be having a facepalm moment



The maf sensor is the only thing left that i can suspect..ever since i owned the car, i've been running on junkyard maf sensors and they seemed to be working okay until 3 weeks ago..



so i ate $350 and bit the bullet on a new factory hyundai MAF..

I'm already conteplating a new car if this fails.oh well, X-D's sure are much nicer cars.

Have you checked for any air leaks?

Commonly the intake manifold gaskets fail.

finally fixed after a hair graying session of diagnostics and a bucket of parts needlessly changed.



it was the purge control valve, but i never suspected it since it didn't throw a Purge valve related code, only the p0446 which points to the close canister valve, the evap system found a blocked vacuum line and for some reason accused the CCV valve of being stuck closed when it was the Purge control valve, I noticed that the engine was hissing near the purge control valve area but thought it was normal since the air intake feed tube for the CCV was below.



i went to radio shack and bought some alligator clips, 9volt pigtail, and a 9volt battery..tested my old Purge valve..it faintly clicked..shot some brake clean and blew compressed air though the purge control valve..click got much louder and died down after 12 to 20 tries with the battery test..shot brake clean and blasted air one more time and put it on my car and started her up, engine load and maf were reading normally for the first 15 seconds then crapped out again to 1.18 load and less than 2 g/s of maf signal..



went to autozone and bought another dorman Purge valve and it's finally fixed..and to believe that the past month i was so frustrated and wasted so much money.



oh well, now i have a surplus of good used maf sensors, a good used CCV valve..lemme know for dibs.

Fixed is fixed, anyway. Glad to know it's going again. :beercheers:

the direct fit catalytic converter and 2.25 midsection exhaust with a 22 inch resonator makes it even more exciting to drive..smooth hushed deep tone and defintely noticable 6k power gain..this was one of the changes i made during troubleshooting..thinking the clogged pipes was source of hesitation.