I now have a P0102 code.....I've replaced the camshaft sensor and the crankshaft sensor and the P0340 is gone. I still have the p102 code. I've dissasembled the MAF and cleaned it but still have the code. The voltage on the yellow wire at the MAF is 5v with the ignition key on. There is no voltage on the pink wire. Should there be 12v on the pink wire?? I've checked the black wire to ground and there is zero resistance. Where do I go from here??

 

Sounds like you have a defective MAF sensor. The pink wire is the output to the PCM. You really should have a scanner to check the output of the MAF sensor as it may not be readable by a DMM (you have to be able to read the frequency).

 

If the pink is the output to the PCM then shouldn't the yellow wire have 12v at the MAF with the key on? When I did a search on "P0102" I read that there should be 12v at the MAF on the yellow wire...I only read 5v at the MAF on the yellow wire. I don't have a scanner to check the frequency so if the consensus is that the MAF is defective I'll spend the $100 and buy a new one.

 

The MAF gets fed +5V from the PCM. This is its reference voltage. It then has a ground and the signal return to the PCM.

 

For some reason, I had the same 0102 code on my '01 Blazer about a year ago. I did all the cleaning and replaced my MAF sensor, to no avail. I finally brought it in and it ended up being a clogged catalytic converter of all things. I figured one, no deal, but there are 2 on the '01 models. Had both of them replaced and have had no issues since then in regards to that error.

 

Is there any drive ability issues? Reason I asked is Howlingx has a valid point. If a pre-convertor O2 sensor is pulled and there is a drive ability issue-is it now better? Had a handful of similar situations to this and had it be the convertor and with 189,000 miles-could be time for the third convertor(or who knows)..Good luck-Jerry[:@]

 

Well I spent $100 on a new MAF and still have the P0102 code. The cat is gutted but maybe there is a piece in there that moved?? I've sprayed starting fluid all around the intake and the engine in gereral but no sign of an intake leak.
The only driveability problem is at hwy speed the tranny bucks. Also a cold engine the rpm is all over the place until I put it in gear and drive or I rev it.

Where are the other ends of the MAF sensor wires? Maybe I need to check for a broken wire. Does anyone have a schematic??

Also, I have a Actron code reader and with the engine running if I erase the code my rpms drop for a second until the "check engine light" comes back on...then the rpms go back to where they were.

1-26-09-new throttle position sensor....still got P0102 code!!!

Any other advice would be much appreciated.....

 

Update: I bought an AutoTap system and have found that the MAF frequency is 0 even after I went back and got a 3rd MAF sensor just in case the 2nd one wasn't any good.

Could it be my computer (ecm,pcm) ? Can any auto store test the pcm/ecm??

 

If you have 5V and a good ground at the MAF, but are not getting the signal back to the PCM, then I would check continuity on the MAF wire to the PCM.

 

I did the followingfrom one of your other postings.... and the continuity was fine to cavity 28. From what I understand the yellow wire is the 5v signal and the pink wire carries the output back to the "brain". And I had 5v on the yellow but nothing on the pink wire while the engine was running....

Check for power on the right pin (pink wire) when looking at the connector with the catch up. Check for ground on the center pin (black wire w/ white tracer). You could put a volt meter with the black lead on the center pin and the red lead on the right pin and it should show +12V with the key on, but it's best to check both independant of each other. Then check continuity between the left wire in the connector at the MAF sensor (yellow wire) and cavity 28 on the red plug on the PCM (located on the passenger side attached to the top of the coolant overflow bottle.