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2004 C5 Coupe. Stock long block 1-7/8 LT headers FAST 92 w/ LS2 90mm TB LS3 air intake with LS7 MAF
Vehicle has been setup like this for almost a year and has been running fine (excellent actually, drives fantastic and pulls strong). Then out of no where I started getting a P0102 "Mass Air Flow MAF Circuit Low" codes (been happening for about 2 weeks now). I clear the code and within 5 mins of driving, it comes back. I've checked the pins and jiggled the plug to see if it could be lose (while logging at idle), but everything is good.
I came across this on LS1Tech while researching:
P0102
DTC P0102 Mass Air Flow (MAF) Sensor Circuit Low Frequency
Circuit Description
The Mass Air Flow (MAF) sensor measures the amount of air ingested by the engine. The direct measurement of the air entering the engine is more accurate than calculating the airflow from the MAP, the IAT, and the engine speed (speed/density). The MAF sensor has a battery feed, a ground, and a signal circuit.
The MAF sensor used on this engine is a hot wire type. This engine uses the MAF sensor in order to measure air flow rate. The MAF output frequency is a function of the power required to keep the air flow sensing elements (hot wires) at a fixed temperature above the ambient temperature. Air flowing through the sensor cools the sensing elements. The amount of cooling is proportional to the amount of air flow. The MAF sensor requires a greater amount of current in order to maintain the hot wires at a constant temperature as the air flow increases. The MAF sensor converts the changes in current draw to a frequency signal read by the PCM. The PCM calculates the air flow (grams per second) based on this signal.
The PCM monitors the MAF sensor frequency. The PCM determines if the sensor is stuck low, stuck high, not providing the airflow value expected for a given operating condition, or that the signal appears to be stuck based on a lack of signal variation expected during the normal operation. This diagnostic tests for too low an airflow rate. This DTC sets when the PCM detects that the MAF sensor frequency is below a predetermined value.
Conditions for Running the DTC
- The engine speed is greater than 300 RPM. - The system voltage is at least 8.0 volts.
Conditions for Setting the DTC
- The MAF frequency is less than 10 Hz. - All conditions met for 1 second
This seems to fit with what other people who get this code experience (MAF Hz go to 0 for a period of time). So tonight I made sure to clear all codes and went for a 10 min drive while using VCM scanner (HPTuners) to see if the MAF frequency actually ever went below 10Hz (zero). It didn't.
On review of the log file (attached), the lowest Hz value the MAF ever registers is 947.75 Hz (never zero). It is a bit odd because this happens at 3000 RPM, but the throttle is closed as I'm exiting the highway on the down hill off ramp. Just before the 947.75 dip, the frequency was 2,626 Hz @ 2,987 RPM. It dips to 947.75 @ 3,046 RPM Then back up to 1,459 HZ @ 3,122 RPM. But this dip all happens in less than 0.2 seconds according to the time stamps on the log.
Other than that point, the other data points are all above 1000 Hz and the vehicle always drives "normal" (no hesitation/bucking/etc.).
Based on the "Conditions for Setting DTC" outlined above (less than 10Hz for 1 second), it never should have set. Yet, when I got to where I was going the code was back.
Hitting less than 1khz is pretty weird. You might consider swapping mafs.
I tried that last night. Got a brand new MAF from the dealership and no change. I even dug up an old log file from almost a year ago (long before I had issues) and it had very similar readings (including dips below 1K on long deceleration).
Originally Posted by NicD
Are you using a wiring harness adapter for the MAF or did you cut/splice the wiring?
No, it's cut and soldered. I've tested the voltages, checked the ground resistance and even confirmed the pins are nice and tight. It's nuts because as I said, everything worked fine for almost a year and then one day is threw a code. Now the code is persistent.
Subbing to this as I am having similar issues with my LS swapped Nova. I get code p0101.
p0101 is due to the MAF and VE table being too far apart. You need to tune your VE table (using a wideband O2) to be correct (set MAF Frequency Fail High to 0 Hz), then tune the MAF to match.
Or you can just fudge the airflow delta by multiplying the table by 1.5, but that's masking the issue. It would be better to fix the VE table since having a MAF and VE table that are not matched can lead to poor drivability and throttle response.
12-05-2019, 10:30 PM
P0102 - MAF never goes to 0 HZ 
