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Hello, I've walked around this forum as an interloper and learned some really great information - thank you all. However, my wife's 2004 Corvette standard model 6spd/164,000 mile showed no charge at the gauge. Alternator and battery checkout as good. After visiting here I learned to remove the ignition switch/clean contacts and this remedied the gauge issue/by way of instructions from a member who's name I don't recall but, it's often mentioned and praised. The car has been throwing traction control and ABS codes "every once and awhile" and they'll remove themselves while driving for alittle while...? My other issue which is the purpose of this post is because I took the car to a friend who's a Porsche repair guy and he used a scanner and a volt meter to diagnose the following. Mass Air Flow sensor isn't happy, FWD and AFT 02 sensors show failed heating elements. Once we began checking fuses in the engine compartment we learned I have voltage (with key in the on position) to all fuses except #15 or the fuse for the 02 sensors. Has anyone ever experienced this before and if so, is it the fuse box itself? Sorry for the long winded explanation. Thank you for your time.
Welcome Troy !!...OK, so we are assuming your gauge issue is fixed. Actually I had the same Service A.H. and T/C messages pop up last night while I was doing some injector testing on my '01...I'll let you know what I find...it may be my battery was a little weak but I'll pull out the scan tool tonight and see if I have any DTC's...now what do you mean that "the MAF isn't happy"...I can't find a "MAF isn't happy" DTC...LOL !!...what exactly did he mean ??...now fuse 15 feeds ALL 4 O2 sensors. So if you take a 12 volt test light BOTH test points on that fuse don't light up ??....See if you have power to fuse 5 (ABSTRNS)...ALSO that circuit feeds the EBCM...maybe the cause for those intermittent ABS/TRAC codes ??...if someone has an '04 wiring schematic can you verify the wiring...I can't currently access my wiring data base
...do you have the ABS/TRAC codes current now ??....those 2 fuses are powered off the same circuit wire...if Fuse 5 is powered you may have a fusebox issue with that pin or an open in the wire between the pin and upstream to the IPC fuse block (pictured)...Now my wiring is for an '01.
Welcome Troy !!...OK, so we are assuming your gauge issue is fixed. Actually I had the same Service A.H. and T/C messages pop up last night while I was doing some injector testing on my '01...I'll let you know what I find...it may be my battery was a little weak but I'll pull out the scan tool tonight and see if I have any DTC's...now what do you mean that "the MAF isn't happy"...I can't find a "MAF isn't happy" DTC...LOL !!...what exactly did he mean ??...now fuse 15 feeds ALL 4 O2 sensors. So if you take a 12 volt test light BOTH test points on that fuse don't light up ??....See if you have power to fuse 5 (ABSTRNS)...ALSO that circuit feeds the EBCM...maybe the cause for those intermittent ABS/TRAC codes ??
...do you have the ABS/TRAC codes current now ??....those 2 fuses are powered off the same circuit wire...if Fuse 5 is powered you may have a fusebox issue with that pin or an open in the wire between the pin and upstream to the IPC fuse block (pictured)...Now my wiring is for an '01.
Here's something new and disturbing, took the car around the block and it wouldn't accelerate but, instead was stumbling like on a rev red limiter and now a check engine light is shining bright...
Well, better bring your car back to your repair guy with the scan tool and see what DTC's you have...you have a combination of your O2 sensors running in "open loop" (the engine computer is going to run based on how it thinks it should be running) with those open O2 heater circuits inoperative and if it's in "closed loop" the engine computer is going to see a RICH signal and reduce "injector pulse width"...in plain English the car will fall flat on it's face when you step on the gas !!...and also you a MAF that "isn't happy" !!...good luck !!
I thought I'd gotten this posted for you just before the "new and disturbing" reply.
I checked the voltage at fuses #5 and 15 yesterday as you'd suggested.
#5 with key off and grounded to battery.
0.2 millivolts.
With keys on 5.0 millivolts
#15 with key off and grounded to battery.
0.2 millivolts.
With key on 4.5 millivolts.
Using a test light I have power across all fuses except # 5 and # 15.
Thank you for your time.
With no power at both fuses you’ll have to pull the fuse box under hood and check pinA7 on the C2 connector and if no power there work your way back to the IP fuse box (passengers footwell) and check Pin F7 on the C1 Connector (orange wires)...GOOD LUCK !!
Thank you for your advice, guidance and direction. I measured both locations as directed. I'll take the beginners assumption that the engine compartment C2 is the gray center plug and C1 connector of the fuse bix passenger foot well is also the center plug?
Using a test light I'm getting zero voltage at either of those locations - again assuming I'm in the correct plugs.
Attached are photos of the locations I tested. Any further direction will be most appreciated.
And of course if I'm off course please set me straight. Engine compartment center plug Passenger foot well.
02 Sensor fuse has no voltage
