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2009 2LT here with 38k miles
Check engine light led to diagnosis that MAF sensor needed replacement
I replaced it and now light came back! Shop saying that I am only getting 4V of power to MAF when it should be 5V, need to keep car for entire day to check wiring aka $$$$$
With the MAF sensor unplugged you should be seeing 5 volts on the signal wire...were they seeing 4 volts on the scan tool or with the sensor unplugged at the signal wire ??...if 4 volts unplugged I'd be looking at the connector first for a corroded pin...they should have a piercing probe where they can check the voltage upstream of the pin...also a good idea to go right to the other end of that circuit at the ECM and see if there is 5 volts there...they have the car so I don't think there is much we can do on this end...does that shop not know how to proceed with the diagnosis ??
Shop said: it's around $90-150 for diagnostic depending on how long it takes. Then once we figure out exactly what's wrong we can get you a price to fix it. Worst case scenario, if it's a PCM issue that we cant fix, you would have to take to dealer
If the connector is good at the MAF sensor they should be checking the same connector pin at the ECM for pin fitment or corrosion too…if is 100% an ECM change you don’t have to bring it to a dealer for programming…you should call around your area for a shop that can program it for you…these guys are in your area I believe…best in the business as far as diagnostics and programming…John Thornton is probably one of the 2 top diagnosticians in the country !!
All I can tell is that you have a faulty MAF sensor. You can check it with an ohmmeter. The resistance should be very high. Unplug it from the engine. The resistance should be very low. Or you can check it with car running and you can monitor the resistance. If the resistance is changing during driving, then it is probably faulty. Best of luck.
Well first off WELCOME to the Forum !!… I don’t know where you’re getting your info from but you don’t check resistance with the car running on the MAF…with a scan tool you check the MAF voltage or frequency which should be changing…a friend has done a great 3 part video on MAF sensors understanding and diagnostics...might be helpful !!…thanks !!
If you do use one of these guys they WILL find your problem…let us know if you do use them and what they find…I have attended some of John Thornton training seminars over the years and this guy knows his stuff…one of the top instructors in the country !!
Need some advice guys!
