P0130 O2 Sensor Circuit Malfunction After Test Pipe Tried Everything HELP!!!!!

[SanBluB51.8T]

Hey all I have a 01.5 1.8 a4. I am having a P0130 issue P0130 O2 Sensor Circuit Malfunction when read with VCDS, that i cannot solve for the life of me when the engine warms up it has a surging idel on my boost gauge going from 22 to 24 and eventually throws a P0130 O2 sensor circuit malfunction. Bought two brand new exact exact o2 sensors and didn't help i have a 01.5 B5 1.8 A4 with custom tune bosch 440CC injectors with ECS spacers and bolts 034 test pipe borla exhaust 3" MAF with cone filter and K04 borg warner turbo apr inlet hose dahlback DV Valve. This has been driving me nuts for a couple months i cant seem to pin point it... Any help or insight on this would be more than greatly appreciated. Thanks

Anthony

[Wrath And Tears]

Sounds like a wiring issue to the O2S then. I am assuming that you normally get a different code when you run a test pipe without a spacer for the rear O2S, having to do with being too rich or lean. So that really only leaves the wiring.

That being said I don't believe your O2S issue would cause your surging at idle, mainly because the O2S are not used when the car is first warming up, as they and the cat need to be hot before the system will start working. I would look for false air, or a possible faulty MAF.

[SanBluB51.8T]

replaced MAF and changed a couple old vaccum lines didn't solve it but ran a little better.. the surging doesn't start until the car is fully warmed up so. So I guess when its warmed up it starts surging because the O2S Is warmed and starts reading ausing surging.. I would hope the new oem sensor wasn't broken from the start I don't think it is because when I installed it noting changed same code and surging, but when I unplug it I get P0035 or P0135 on of those two I forget.....

[SanBluB51.8T]

can anyone else shine some light on this issue??

[SanBluB51.8T]

TTT Anybody???

[Tanzimur]

try a tbody adaptation?

[Murph_129]

If the primary and secondary are the same part number, try switching those first.. In the off chance one was bad from the retailer, its pretty unlikely both would be bad.. If the problem persists then you've got an issue from the harness back to the ECU.. The connections for the 02 sensors are on the firewall underneath the coolant tank.

[SanBluB51.8T]

thanks for the couple responses to my thread... i tried a TB adaptation and im not sure if it went through.. couldn't hear anything im not a pro with VCDS... i also have looked at the 02 sensor wiring harness and clips under the coolant tank. i wounder if a coolant temp sensor would possibly be an issue im noticing the car takes a while to fully warm and heat isn't the greatest the needle goes higher in the middle when just the ignition then goes slightly under when turned on...still cant figure this nagging thing out!!!

[SanBluB51.8T]

Bump can someone please help this is driving me nutts!!!

[ray4624]

the 02 sensors should be different. They are not the same. OEM even has different colored connectors. Start there and figure out which one you have 2 of.
https://www.ecstuning.com/Audi-B5_A4....8T/ES2539127/
https://www.ecstuning.com/Audi-B5_A4...-1.8T/ES11898/