need some codes help
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From: Warrenton, va
need some codes help ok, just replaced the MAF and both O2's last night..... resset the computer even used a code scanner to make sure it was reset.
anyway it threw codes today again....
MAF or VAF voltage low
o2 sensor heater circuit low bank 1 and 2...... any clue what i can do now..... car doesnt feel like its running bad at all as a matter of fact better than last week.
previous dyno numbers cam only were 385/369tq
now with heads, cam, bolt ons etc. 351 hp ??? tq cant remember
anyway the graph looked like a lie detector test and the car felt like crap.... like running on 6 or 7 cylinders in safe mode crap.
trying to figure out wy im throwing those codes
anyway it threw codes today again....
MAF or VAF voltage low
o2 sensor heater circuit low bank 1 and 2...... any clue what i can do now..... car doesnt feel like its running bad at all as a matter of fact better than last week.
previous dyno numbers cam only were 385/369tq
now with heads, cam, bolt ons etc. 351 hp ??? tq cant remember
anyway the graph looked like a lie detector test and the car felt like crap.... like running on 6 or 7 cylinders in safe mode crap.
trying to figure out wy im throwing those codes
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Joined: Nov 2001
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From: Lake Zurich, IL
Check the Engine Sensor fuse ... that's the first place to check since they all use this fuse (MAF and O2s) for power
If that's not it, then perhaps a bad common ground... on the sticky at the top of this section , there's a web site that has diagnostic procedures... pick a code and walk through them (it'll walk you through all the wiring) if it's not the fuse... but check the fuse first (engine sensor fuse is under the hood)
Settings the O2 codes is forcing you into open loop and the MAF is forcing you into open loop speed Density so a car not tuned for it will suffer from loss of power and horrible gas mileage
If that's not it, then perhaps a bad common ground... on the sticky at the top of this section , there's a web site that has diagnostic procedures... pick a code and walk through them (it'll walk you through all the wiring) if it's not the fuse... but check the fuse first (engine sensor fuse is under the hood)
Settings the O2 codes is forcing you into open loop and the MAF is forcing you into open loop speed Density so a car not tuned for it will suffer from loss of power and horrible gas mileage
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From: Warrenton, va
Originally Posted by horist
Check the Engine Sensor fuse ... that's the first place to check since they all use this fuse (MAF and O2s) for power
If that's not it, then perhaps a bad common ground... on the sticky at the top of this section , there's a web site that has diagnostic procedures... pick a code and walk through them (it'll walk you through all the wiring) if it's not the fuse... but check the fuse first (engine sensor fuse is under the hood)
Settings the O2 codes is forcing you into open loop and the MAF is forcing you into open loop speed Density so a car not tuned for it will suffer from loss of power and horrible gas mileage
If that's not it, then perhaps a bad common ground... on the sticky at the top of this section , there's a web site that has diagnostic procedures... pick a code and walk through them (it'll walk you through all the wiring) if it's not the fuse... but check the fuse first (engine sensor fuse is under the hood)
Settings the O2 codes is forcing you into open loop and the MAF is forcing you into open loop speed Density so a car not tuned for it will suffer from loss of power and horrible gas mileage
TECH Senior Member
Joined: Nov 2001
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From: Lake Zurich, IL
no... it's marked as "Engine Sensor" (may be missing a few letters, but it reads Engine SEnsor), and it is the fuse for the O2 sensors and MAF ... not the same as PCM Bat or PCM Ign ... i don't recall what amperage it is off hand... but on the covers that go over the fuses it says Engine Sensor
If you replaced 2 O2s and a MAF and still have the problem... then this is most likely the problem (blown fuse) since all these items are on a common power
If you replaced 2 O2s and a MAF and still have the problem... then this is most likely the problem (blown fuse) since all these items are on a common power
Last edited by horist; Mar 16, 2005 at 08:04 PM.
TECH Senior Member
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From: Lake Zurich, IL
the code will come on when the conditions for setting the DTC are met... this is usually 1 driving cycle or x time after the cycle... or sometimes it takes 2 instances to set it... but the fact that it's setting the SES at all means a problem exists...
Thread Starter
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From: Warrenton, va
ok usually it does pop back on when the car is driven for an extended period of time on first startup after reset. or on the second drive right away. illl definatley check that fuse.....
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Thread Starter
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From: Warrenton, va
i could just about kiss you right now......j/k.....it was the damn fuse.....fixed it and now the car by the seat of my pants feels like it gained 50hp on motor. well it will be going to the dyno day next sat and we'll see if there is any actual difference
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Verdad Gallardo TECH Senior Member
Joined: Nov 2001
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From: Lake Zurich, IL
cool 
Now the next thing is to see if it blows again... fuses don't blow unless there's a short somewhere... make sure your O2 wires are tied up away from the headers ... when I was blowing my Engine Sensor fuse it was because the driver side O2 wires hit the header and melted through... and were thus blowing that fuse
Were either of your old O2 wires burnt through at all? (when you replaced both O2 sensors)
Now the next thing is to see if it blows again... fuses don't blow unless there's a short somewhere... make sure your O2 wires are tied up away from the headers ... when I was blowing my Engine Sensor fuse it was because the driver side O2 wires hit the header and melted through... and were thus blowing that fuseWere either of your old O2 wires burnt through at all? (when you replaced both O2 sensors)
O2 Sensor i have been following the progression as i have a very similar problem, can i too get help? 2002 Z28 - dropped ZO6 crate, ok until i added SLP long tube headers. rear O2 dis-abled by PCM - CARPUTING LS1 EDIT LS6. driver's side front O2 is coding reading lean, someone read it for me and said the voltage just drops off. the performance is great, but it is following the same open loop cycle. replaced MAF for cold-air, checked for leaks as best i could, replaced O2 sensor, checked engine sensor. i lost my custom computer and had to use a plain LS1 re-flash to return home 500 mi. and it never coded once even though it was not running correct program. there is really no-one that truly gets into this in my area, if i drove into a GM garage is there anything they could do. help please. cbruer