SES Light Code 0102

[ted-hurst]

I have a 1999 Chevrolet K2500 Suburban with the 7.4L and except for a K&N filter it's all stock. The truck has 100K and all maintenance has been done and when we coming back from a road trip, the truck started idling rough and the SES light came on. When I got home I scanned the computer and code P0102 (Mass Air Flow Circuit Low Input) recorded, I replaced the Mass Air Flow Sensor, checked the air filter (was clean and not over oiled), made sure all the ducting was tight, made sure the whole intake was clean and checked the wiring which looked good. I had not had any problems until this weekend and now it's running rough (Runs rough at first start up and at idle but drives okay through the rest of the rpm range). Where do I need to look next?

 

Thanks

[GM-Tech]

There's no place to look next. You need to go back over what you've already checked and make sure you haven't missed something. If the air intake isn't restricted, the wiring is perfect and the MAF is new, there's not much left.

 

It could be the rare instance that a PCM causes this kind of problem, but that's usually the last place I'd look.

 

Are you absolutely, positively sure there's noting in the air intake forward of the air cleaner assembly? Seen more than a few plastic bags sucked into a wide variety of vehicles.

[ted-hurst]

I checked all the way up to the air cleaner but not forward, I'm going out to check that next. I noticed that it only happens at idle or off idle, when I'm driving (1500+ rpm) it drives normal.

 

Thanks

Ted

[ted-hurst]

I went back and checked the air intake and its clean. I also went back and found I wasn't getting the correct voltage to the MAF sensor so I traced it back to the ENG-1 fuse (pink wire) and found the fuse popped. I replaced the fuse and cleared the codes and as soon as I started it, the fuse popped again. We troubleshot it further and the only time the fuse pops is when the vechile actually starts moving (forward or reverse). We started the vechile and let it sit for over a minute in PARK, REVERSE, NEUTRAL and DRIVE and everything is good, but as soon as the vechile moves the fuse pops. It also seems like it shifts from gear to gear firmer. Any assistance would be appreciated.

 

Thanks

Ted

[GM-Tech]

ENG-1 powers the EVAP purge and vent solenoids, the O2 heaters, the cam position sensor, the MAF and if you have AIR injection, the A.I.R. intake recirculation relay.

 

If it pops when you start moving, I'd be looking for a wire that's rubbed through and just the right vibration makes it ground out. O2 sensors in that hot exhaust would be a good starting place.

[ted-hurst]

The problem turned out to be a short in the wiring harness. I call the local GM dealer and the first thing he said was to check the wiring harness by the firewall and transmission tunnel. I checked everything else and this was the problem. The sensor side of the oxygen sensor was grounding out, not the heat side.

 

Ted