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Ok, while idling along at a stop light, going to make a left hand turn, we must have been sitting there for about 20 seconds (long light), anyway, i noticed the check engine light came on, and i thought "uh oh" because, my mom is afraid of check engine lights, like its some kind of phobia, (when it came on in the minivan, it cost like 500 bucks) BUt anyway, she didnt notice, and when i was about half way through with the left turn, the light went off and has been off ever since! I pulled codes, i got a 511, and 113. I dont know what the 511 means, somthing about read only memory, but its beyond me how to diagnose it, or what it really means. But the 113 is "Air charge Temperature sensor below minimum voltage" Okay, where is ths "Air charge temperature sensor" on my truck, then only thing i have is a MAF, and thats it. Is it on the intake manifold by chance?
From my Haynes manual: 511= Read only test failed - replace PCM.
Right there is where I would clear the codes & test again later.
The AIT sensor is located in the plastic air duct just before the throttle body.
AL.
I wonder if the diablo chip i bought has anything to do with the 511 code? I checked out autozone's website, and i thinik i know where the "air charge temperature sensor" is. I know for a fact that its not anywhere on the intake tube, i removed all of that, and never saw any sensor, and looked it over again, and still, nothing. On autozone's website, it said its in the intake manifold. So, i'll check that out. If i could get a Pcm from a junkyard with the same code as my old one, will i have to have it reprogrammed for my gear ratio's and stuff, or will that all be the same since they are the same code?
Okay, but the engine was completely warm when the check engine light came on, and i only did the koeo test, i didnt do a koer. These codes were in the memory, i wonder which caused the CEL?
I would clear the codes, drive it for a few days and then do KOEO & KOER and see what you get. If you still get the 511, try it without the chip.
I concur. I suspect too that the chip might be related to the 511 code. I've seen it happen to a few SHO owners, now that I think of it.
I think your ACT (actually, by '94 it's called the Intake Air Temperature sensor, or "IAT") is screwed into your upper intake, on the same side where the Idle Air Control valve is mounted. The IAT might be hidden under some plug wires...
With the key on, the voltage at the connector should be 5 volts.
Haynes quote:
Measure the resistance across the sensor terminals. The resistance should be high when the air temperature is low.
Next, start the engine and let it idle (cold). Wait a while and let the engine reach operating temperature. Turn the engine off, disconnect the IAT sensor and measure the resistance across the terminals. The resistance should be low when the temperature is high. If the sensor does not exhibit this change in resistance, replace it with a new part.
AL.
Okay, checked it out, the engine was still kinda hot, it ran up 8k ohms, i unscrewed it, and tooka look at it, and it seemed to be all oily? with some gunk on it, well, i first let it cool down, and checked the voltage, which was around 20k ohms, which is correct. I then sprayed carb cleaner on it and cleaned off all the gunk on it, and sprayed some carb cleaner in the intake manifold through the hole i unscrewed the sensor from, everything seems to run okay, so tommorow, i'll reset the computer and see what happens. I wonder why it threw out that code?