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Discussion Starter #1
Hi All -

I'm trying to help a friend repair a 2007 4 cylinder Malibu that's throwing a P0449 Evaporative Emission System Vent Valve/Solenoid Circuit code.

Back story - the fuel level sender failed, causing the initial P0461/0462 codes that got us started down this rabbit hole. I can't recall if it was also throwing the vent solenoid circuit code initially, too, but don't think that it was. I suspect that in the process of poking at it and trying to disconnect the fuel tank connector at the body that I might have broken a wire as we were initially troubleshooting it with the car on the ground with limited space to get at things and even see how to separate the connector. Regardless, we found that the fuel sender was bad and elected to drop the tank and replace the whole assembly, fuel pump and all.

Shortly before dropping the tank, another scan revealed the evap solenoid circuit code, too, so we bought a replacement solenoid and installed it while the tank was out to do the pump/sender assembly. Of course, to my chagrin, the old solenoid appeared to be ok when ohmed out, but we put the new one in anyway. A continuity check on the ground before reinstalling the tank indicated that the wiring from the main connector through the solenoid was good, with a resistance of around 20 ohms, IIRC. Once everything was back in the car, the evap solenoid circuit error code persisted.

I saw a video online where someone showed finding breaks in the wiring at the point it emerged from the connector, so I bought a pair of insulation piercing probes, got the car off the ground again, and checked for continuity, this time an inch or so away from the body side connector, thereby checking the continuity through the connector; we still had a complete circuit and similar readings to what I saw looking directly into the solenoid. Given this, it seems that the circuit through the connector and tank wiring is ok, and I suspect a break (or possibly an electronic problem) exists somewhere upstream of the connector on the bottom of the body (This is the connector that ties the tank circuitry into the car's harness; it is located near the front of the tank on the passenger side of the floorpan, with the e-brake cable positioned perfectly to make access more difficult). The trouble is, I haven't been able to find any schematics of the circuit to help with further troubleshooting - had downloaded a manual online that lacks the schematics; bought a Haynes manual, it has some of the body electrical schematics but of course not what I need, and internet searches have not gotten me anywhere.

If what I gleaned from reading online is correct, one wire feeds +12V to the solenoid, and it is activated when the drive circuit pulls the other wire to ground - please correct me if I'm wrong. I haven't checked yet for +12 on one of the wires yet as I learned that after the last time we had the car up - if it's confirmed that my understanding of the circuit is correct I'll check that straight off tomorrow night. For what it's worth, I have also just gotten a more advanced scan tool that will let me activate circuits for troubleshooting purposes, so my hope is that will help too.

Can anyone here either direct me to a schematic of that circuit, post a schematic of that circuit, or at least tell me where the harness is routed and what the wire colors are so I can explore things further up the line to try to isolate the problem? Additionally, if anyone knows of any common failures that look like this and can offer insight I'd be very grateful.

Thanks for any assistance, and if I can answer any questions about things I might have missed above, please ask.

Best

-Pat
 

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Discussion Starter #3
Thanks for the input.

The link takes me to Twingo Wiring Electric Diagrams. It then directs me to create a free account at a site called "honiedfun.com", but once there I'm unable to find anything related to wiring diagrams or car repair... Is that were it was supposed to go?
 

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Ya.... i seen the picture.... but ya it wanted me to make an account.....screw that.... i could find a way to just get the dang diagram unfortunately. ...was hoping you could pull it up ( thinking my wonky old tablet was to blame or something )

Tried looking around google but just couldnt pull up exactly what you need.... wondering if a cheap haynes manual would have one
 

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Discussion Starter #5
Nope, no such luck. I remember finding a site with diagrams a year or two back when helping another friend fix his Saab, but can't for the life of me find it now, and he doesn't remember. Now to go cancel the honied.com account.

I bought a Haynes manual from Amazon because I've found them to be better than Chilton, but alas nothing more than some body wiring diagrams - lighting and the like, so no joy there. Made the rounds last night to the local auto parts stores hoping to find a Chilton manual they might let us look in to confirm it had what we needed before we bought it, but no joy - no one has it. I'm reluctant to drop another $25 to buy one from Amazon sight unseen not knowing if it has the schematics.

It's aggravating - searches bring up too much unrelated crap.

Thanks for the suggestion, though - I do appreciate your effort.
 

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Haynes and Chilton are useless. I use alldatadiy.com and get a subscription for all my cars.
It's a full shop manual with all the diagrams for every circuit. Intense to navigate but complete info for every component.
The money you waste on the others pays for it. I don't trust any of the free stuff out there if you can even find it. Really need a laptop or desktop to properly follow the diagrams, phone screen is not big enough.
 
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Discussion Starter #7
Excellent - thanks for the tip! I wasn't aware of that site - sounds like it will provide what I'm looking for.
 

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Haynes and Chilton are useless. I use alldatadiy.com and get a subscription for all my cars.
It's a full shop manual with all the diagrams for every circuit. Intense to navigate but complete info for every component.
The money you waste on the others pays for it. I don't trust any of the free stuff out there if you can even find it. Really need a laptop or desktop to properly follow the diagrams, phone screen is not big enough.

Thank you thank you thank you!! Signed up for the service, and have found the schematics I need. Much appreciated!

-Pat
 

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Hi All -

I'm trying to help a friend repair a 2007 4 cylinder Malibu that's throwing a P0449 Evaporative Emission System Vent Valve/Solenoid Circuit code.

Back story - the fuel level sender failed, causing the initial P0461/0462 codes that got us started down this rabbit hole. I can't recall if it was also throwing the vent solenoid circuit code initially, too, but don't think that it was. I suspect that in the process of poking at it and trying to disconnect the fuel tank connector at the body that I might have broken a wire as we were initially troubleshooting it with the car on the ground with limited space to get at things and even see how to separate the connector. Regardless, we found that the fuel sender was bad and elected to drop the tank and replace the whole assembly, fuel pump and all.

Shortly before dropping the tank, another scan revealed the evap solenoid circuit code, too, so we bought a replacement solenoid and installed it while the tank was out to do the pump/sender assembly. Of course, to my chagrin, the old solenoid appeared to be ok when ohmed out, but we put the new one in anyway. A continuity check on the ground before reinstalling the tank indicated that the wiring from the main connector through the solenoid was good, with a resistance of around 20 ohms, IIRC. Once everything was back in the car, the evap solenoid circuit error code persisted.

I saw a video online where someone showed finding breaks in the wiring at the point it emerged from the connector, so I bought a pair of insulation piercing probes, got the car off the ground again, and checked for continuity, this time an inch or so away from the body side connector, thereby checking the continuity through the connector; we still had a complete circuit and similar readings to what I saw looking directly into the solenoid. Given this, it seems that the circuit through the connector and tank wiring is ok, and I suspect a break (or possibly an electronic problem) exists somewhere upstream of the connector on the bottom of the body (This is the connector that ties the tank circuitry into the car's harness; it is located near the front of the tank on the passenger side of the floorpan, with the e-brake cable positioned perfectly to make access more difficult). The trouble is, I haven't been able to find any schematics of the circuit to help with further troubleshooting - had downloaded a manual online that lacks the schematics; bought a Haynes manual, it has some of the body electrical schematics but of course not what I need, and internet searches have not gotten me anywhere.

If what I gleaned from reading online is correct, one wire feeds +12V to the solenoid, and it is activated when the drive circuit pulls the other wire to ground - please correct me if I'm wrong. I haven't checked yet for +12 on one of the wires yet as I learned that after the last time we had the car up - if it's confirmed that my understanding of the circuit is correct I'll check that straight off tomorrow night. For what it's worth, I have also just gotten a more advanced scan tool that will let me activate circuits for troubleshooting purposes, so my hope is that will help too.

Can anyone here either direct me to a schematic of that circuit, post a schematic of that circuit, or at least tell me where the harness is routed and what the wire colors are so I can explore things further up the line to try to isolate the problem? Additionally, if anyone knows of any common failures that look like this and can offer insight I'd be very grateful.

Thanks for any assistance, and if I can answer any questions about things I might have missed above, please ask.

Best

-Pat
Hi Pat,

I am also helping a friend with the same problem. Did you find where the issue lies? Please keep us updated with your progress.

Thanks,
Erin
 
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