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Chevrolet Express
Platform: GMT Van

MAF sensor fuse?

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Old Jun 24, 2022 | 12:12 PM
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Default MAF sensor fuse?

Do these vans have one? What is it called since MAF is nowhere in the fuse box.
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Old Jun 25, 2022 | 3:33 PM
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We might be able to help you, if you provide the necessary information please.
The model, year, and engine would be very helpful. Thanks.
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Old Jun 27, 2022 | 10:13 AM
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Sorry, 2005 Chevy express cutaway 3500 V8 6.0l Vortec. On a separate post I summarized my situation... I went from 10 engine codes down to 1, p0300 for a while, then, after cleaning the injectors and the throttle plate I am getting p0174 and p0300.
I Spent probably 20 mins with the engine running spraying the throttle body and plate with carb cleaner and during that whole time not a single code. Reconnected MAP sensor and air filter, and p0174 and p0300 came back.
Can a bad MAP sensor cause a lean condition only on bank 2?

Last edited by vdocad; Jun 27, 2022 at 11:41 AM.
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Old Jun 27, 2022 | 10:47 AM
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Ok, just came back from checking codes again... Now p0174 is gone but I get p0300 at idle and if I clear the codes and increase the RPM to around 2500 I get p0308. This was verified a couple of times. Injector 8 is making the ticking noise. Should I rule out MAP(I did the map sensor tests, freq and voltage and it seemed to be alright but I cannot explain why I got zero codes when the MAP was disconnected...)
Also SHRTFT B2S2 has always been at 99.2, not sure what this means but it is probably related. All O2 sensors are new.

Last edited by vdocad; Jun 27, 2022 at 12:15 PM.
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Old Jun 28, 2022 | 1:47 AM
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MAP or MAF? I think you're getting confused. They are two separate things. One measures the pressure in the intake manifold, and the other measures how much air is going into the engine. The MAF is the one that needs to be cleaned periodically. Never mind the frequency stuff. How many grams does it read on your scan tool at idle.
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Old Jun 28, 2022 | 8:01 AM
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Originally Posted by vdocad
Also SHRTFT B2S2 has always been at 99.2, not sure what this means but it is probably related. All O2 sensors are new.
Just read this from Blue Driver website, I guess there's nothing wrong with this reading :
"On the majority of passenger vehicles, the post-catalytic converter oxygen sensor (Bank X Sensor 2) is used for monitoring cat health, and does not provide feedback to the ECM for making corrections to the fuel injection rate.
Even though the vehicle does not use post-cat fuel trims, the ECM still reports a value for these trims when requested by a scan tool. As a result, on most vehicles if you monitor short or long term fuel trims for any #2 oxygen sensor you will see a "maxed out" value of 99.2% - this is the ECM's way of reporting that the trim is not in use, and can be ignored.



On the latest versions of the app, post-cat fuel trims will be displayed as N/A instead of 99.2%."
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Old Jun 28, 2022 | 8:09 AM
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Originally Posted by mountainmanjoe
MAP or MAF? I think you're getting confused. They are two separate things. One measures the pressure in the intake manifold, and the other measures how much air is going into the engine. The MAF is the one that needs to be cleaned periodically. Never mind the frequency stuff. How many grams does it read on your scan tool at idle.
I meant to write MAF, sorry. I will post the value later today
The MAF sensor reading is about 6 g at idle with engine warm. So, can I safely say MAF is ok?
I was able to reproduce the same codes, p0300 at idle and if I erase it and increase RPM, I get p0308 only... Engine starts every time with no issues, idles fine and drives fine( I think). Any ideas?

Last edited by vdocad; Jun 28, 2022 at 8:42 AM.
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Old Jun 28, 2022 | 10:01 PM
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Originally Posted by vdocad
The MAF sensor reading is about 6 g at idle with engine warm. So, can I safely say MAF is ok?
Yes, 6 grams/sec is precisely the value you want for your engine. The MAF is doing just fine.


Originally Posted by vdocad
I was able to reproduce the same codes...
The MAF question is now resolved. I will answer your questions regarding the trouble codes in the proper topic. The one you called "Mystery hose, engine codes"
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