Codes 29 and 48
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Codes 29 and 48
So I have a '94 Trans Am GT w/ 190000+ mi. Currently I need to get it smogged tested so that I can renew the registeration after two yrs of planned non-op, but I dont want to take it to a test center until I figure out what's triggering the service engine light soon light. So I went to firestone to get a computer diagnoistic and the codes that were showing up 29, and 48 which they said signaled that there was something amiss with the MAF sensor and the "Air circuit Quad-Drier Error". So my question(s) is what are these two items, more specfically where are they located and how do I repair or replace them?
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From: Hell was full so they sent me to NJ
When you get the codes, all you need to do is look them up in Shoebox's LT1-specific code list.
http://shbox.com/1/Dtcs.htm
The problem with using generic code lists is they point to things like the quad driver modules, which are only applicable to the 93 LT1's.
As noted above, DTC 29 is the AIR pump circuit, and a blown fuse is the most common problem. Fuse blows because the pump rusts up, gets hard to turn, and draws too many amps. If you replace the fuse (in the under hood convenience box) and it continues to blow, simply unplug the AIR pump harness connector, then put a new fuse in, and there will be no code (OBD-I only). You won't have any problems with the emissions check, because the AIR pump only runs for a couple minutes on startup, and I never seen any do a check from a cold start.
DTC 48 is for the MAF sensor. With the key on, check for 12V on the pink wire in the MAF harness connector, when measured across the black/white wire in the connector. If you've got 12V, check the MAF sensor. If you have a frequency meter (included in many low cost multi-meters), look for a signal in the range of 2,500-2,800Hz at idle (measured yellow signal wire to black/white wire). If no signal, MAF is deceased.
http://shbox.com/1/Dtcs.htm
The problem with using generic code lists is they point to things like the quad driver modules, which are only applicable to the 93 LT1's.
As noted above, DTC 29 is the AIR pump circuit, and a blown fuse is the most common problem. Fuse blows because the pump rusts up, gets hard to turn, and draws too many amps. If you replace the fuse (in the under hood convenience box) and it continues to blow, simply unplug the AIR pump harness connector, then put a new fuse in, and there will be no code (OBD-I only). You won't have any problems with the emissions check, because the AIR pump only runs for a couple minutes on startup, and I never seen any do a check from a cold start.
DTC 48 is for the MAF sensor. With the key on, check for 12V on the pink wire in the MAF harness connector, when measured across the black/white wire in the connector. If you've got 12V, check the MAF sensor. If you have a frequency meter (included in many low cost multi-meters), look for a signal in the range of 2,500-2,800Hz at idle (measured yellow signal wire to black/white wire). If no signal, MAF is deceased.
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