No power to O2 Sensors??
04-01-2011, 08:33 PM
#1
No power to O2 Sensors?? I was wiring my trans brake today and was going to use my rear O2 sensor 12v wire as the trans brake's 12v source, and when I was finished it didn't work. A little investigation with a test light showed that my O2 sensor wire wasn't getting any power to it. Not knowing why the sensor wasn't getting any power I turned the ignition on in my car to see if my front O2's were getting any power. After about 10 minutes I went out to check if they had heated up, which they hadn't, so none of my O2's are getting any power.
Also, my starter does nothing when I turn the ignition key... Would VATS have anything to do with this?
I've been working on this car for a while now as a drag project car, so what reasons are there for the O2's to not get any juice? The battery is fully charged. Thanks for any input.
Also, my starter does nothing when I turn the ignition key... Would VATS have anything to do with this?
I've been working on this car for a while now as a drag project car, so what reasons are there for the O2's to not get any juice? The battery is fully charged. Thanks for any input.
04-02-2011, 12:03 PM
#3
I've messed with the wiring on the interior, but all I've removed was the wires that run to the window motors and locks through each door, and the wires that run along the passenger's side of the car back to the radio and such back there. Where are the grounds for the O2's at?
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04-04-2011, 05:29 PM
#8
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Check the grounds in the back of the driver's side head, check the ground at the pass front of the engine bay near the battery. Apparently the O2's ground out to the engine. back the back of the driver's side head.
Heated O2 pinout. The HO2 is powered by the PCM.
-=edit=-
I'm thinking maybe an ignition ground or something to do with the PCM or BCM. Is there any life when you turn the key on? PM ground or power? (You got me wondering now) Does your chime come on with the key?
Links
https://ls1tech.com/forums/pcm-diagn...853-b2961.html
BCM Schematic
http://shbox.com/1/bcm_1996.jpg
Pinout Thread
https://ls1tech.com/forums/conversio...-diagrams.html
Heated O2 pinout. The HO2 is powered by the PCM.
-=edit=-
I'm thinking maybe an ignition ground or something to do with the PCM or BCM. Is there any life when you turn the key on? PM ground or power? (You got me wondering now) Does your chime come on with the key?
Links
https://ls1tech.com/forums/pcm-diagn...853-b2961.html
BCM Schematic
http://shbox.com/1/bcm_1996.jpg
Pinout Thread
https://ls1tech.com/forums/conversio...-diagrams.html
Last edited by bayer-z28; 04-04-2011 at 06:59 PM.
04-05-2011, 01:43 PM
#10
My gauge cluster lights up like normal, and my fuel pump primes audibly. I'm going to check the grounds you've said bayer-z28 thank you. I checked all the fuses and relays, they are all good, no SES lights either...
As far as the BCM is concerned...I unplugged the connection that goes to the window and lock mechanisms since I removed those wires, but why would the BCM have anything to do with the O2's and ignition?
As far as the BCM is concerned...I unplugged the connection that goes to the window and lock mechanisms since I removed those wires, but why would the BCM have anything to do with the O2's and ignition?
I'll check the BCM fuse when I get home
04-05-2011, 03:58 PM
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If the BCM is not receiving power, it will not send power to the appropriate places. I think it sends power to the PCM and VATS. BCM controls a lot of stuff. It's basically a computerized relay for about 15 different things. That's why I was asking if your key chime comes on when you put the key in the ignition. If it is not, it could be a BCM issue. Not necessarily a fuse issue, but I'm not saying it's not either.
But I'm starting to think there are two separate problems here. The ECU only receives signal from the O2's. The fuse block sends power to the heater unit in them, and when they reach temperature, they start bopping around a signal and the PCM picks up on it.
Now if your starter isn't working, that may be a solenoid issue. Or else this whole thing is a power distribution issue. I'd almost check the entire relay/fuse block over on the driver's front and be sure there is power where there should be.
I'll look for some more schematics for ya.
But I'm starting to think there are two separate problems here. The ECU only receives signal from the O2's. The fuse block sends power to the heater unit in them, and when they reach temperature, they start bopping around a signal and the PCM picks up on it.
Now if your starter isn't working, that may be a solenoid issue. Or else this whole thing is a power distribution issue. I'd almost check the entire relay/fuse block over on the driver's front and be sure there is power where there should be.
I'll look for some more schematics for ya.
04-05-2011, 04:23 PM
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AHHA!
BCM ground is the left kick panel.. Check ground there. Black wire, pin 650.
ECU Ground is left rear of engine (Back of the head)
BCM power is Red with a 16ga black fusable link at battery junction block. (Driver's side?) Red wire, pin 102
"Starter Enable. Pin 220 section C5, Dark Green Engine controls system" (Feeds to the ECU, I think) check for 12v.
ECU Ground is left rear of engine (Back of the head)
More here:
http://cs.chevroletclub.net/graphics...g.diagrams.pdf
BCM ground is the left kick panel.. Check ground there. Black wire, pin 650.
ECU Ground is left rear of engine (Back of the head)
BCM power is Red with a 16ga black fusable link at battery junction block. (Driver's side?) Red wire, pin 102
"Starter Enable. Pin 220 section C5, Dark Green Engine controls system" (Feeds to the ECU, I think) check for 12v.
ECU Ground is left rear of engine (Back of the head)
More here:
http://cs.chevroletclub.net/graphics...g.diagrams.pdf
04-10-2011, 12:19 PM
#16
i checked the BCM grounds and fuses, they are all fine....still not getting any crank from the starter or power to the O2's...
The BCM has one connection unplugged from it, the plug that is connected to all the wires that run the power windows and locks, would that have anything to do with this?
The BCM has one connection unplugged from it, the plug that is connected to all the wires that run the power windows and locks, would that have anything to do with this?
04-11-2011, 11:41 AM
#17
I've got a feeling the starter and the O2's not working is related. Do the two ground on a common point? The PCM is grounded and works, I can still mess with the car's tune, so its getting a good reading from the PCM.
VATS is now deleted as well, no help.
VATS is now deleted as well, no help.
04-11-2011, 12:15 PM
#18
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The o2's ground through the block and then back to the chassis. No power to the O2's should be a Ho2 circuit. I'll look to see what I can find.
The starter could be something along the lines of a key'd problem. Track the power distribution back from the relay to what supplies power to the relay, to the trigger.
-=EDIT=-
Ok... The O2's ground the the left rear cyl head. Did you check the separate grounds with a DVOM? Right to the neg terminal on the batt?
Pin/wires 24 + 25 are the grounds for the HO2 circuit on page 20 and 21.
Unless for some fukin reason the engine lost it's ground..
Ground distribution page 26.
http://cs.chevroletclub.net/graphics...g.diagrams.pdf
The starter could be something along the lines of a key'd problem. Track the power distribution back from the relay to what supplies power to the relay, to the trigger.
-=EDIT=-
Ok... The O2's ground the the left rear cyl head. Did you check the separate grounds with a DVOM? Right to the neg terminal on the batt?
Pin/wires 24 + 25 are the grounds for the HO2 circuit on page 20 and 21.
Unless for some fukin reason the engine lost it's ground..
Ground distribution page 26.
http://cs.chevroletclub.net/graphics...g.diagrams.pdf
Last edited by bayer-z28; 04-11-2011 at 12:32 PM.
04-11-2011, 06:23 PM
#19
I have good news! I realized why my starter wouldn't do anything, and that is because I just installed a TH350 and a hurst quarter stick, so my PCM doesnt know when its in "park" because I didn't do the wiring for it yet haha. I feel like such a fool, I'll be taking care of this tonight.
However....this still doesn't explain the O2 problems... The grounds on the back of the head were both checked and passed.
However....this still doesn't explain the O2 problems... The grounds on the back of the head were both checked and passed.
