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Stock Problems/IssuesDiscussions related to warranty related issues and repairs, or other problems with the OEM parts and software for MINI Cooper (R50), Cabrio (R52), and Cooper S (R53) MINIs.
I have the dreaded P2096 code on my 05 R53. While researching last year I came across someone who posted they had a ground fault on the rear o2 sensor but never posted what they did to locate and fix it. I've been trying to months to figure out how to test for a ground fault and fix it.
Does anyone know how to locate a ground fault and correct it? I did a continuity test from the sensor to the ECU and located the 2 wires. That's about as far as I got. According to the wiring schematics I found online line 1 & 2 go to the ECU (which I found), #3 goes to the nowhere that I assume is the ground and #4 goes to 12V+.
My friend that's a mechanic that specializes in German cars had me clear the code but as soon as I shut off the car and turn it back on it comes immediately back on. Which leads him to believe I have an electrical problem not mechanical issue.
Any suggestions would be greatly appreciated.
On the right inner fender, there is a ground lug with many brown wires attached. Remove the bolt, clean the lug and the fender, where the bolt attaches, then check the brown wires, to see if any are corroded, or broken off, fix as required.
Now, with that said, the lower/downstream sensor may be burned out, which will also give you this code. Amazon has a new one for a decent price.
Last edited by ItsmeWayne; Jul 8, 2019 at 09:19 AM.
On the right inner fender, there is a ground lug with mant brown wires attached. Remove the bolt, clean the lug and the fender, where the bolt attaches, then check the brown wires, to see if any are corroded, or broken off, fix as required.
Now, with that said, the lower/downstream sensor may be burned out, which will also give you this code. Amazon has a new one for a decent price.
Thanks Wayne. I'll check it out this weekend.
As for the O2 sensor I replaced them both with Nipo-Denso but the code remains.
Thanks again, let you know how it goes.
Try this:
Disconnect the battery for ten minutes or so, then reconnect and drive it.
Just so you know, It is not uncommon for new sensors to be no good! They are mass assembled and no checked for working.
Try this:
Disconnect the battery for ten minutes or so, then reconnect and drive it.
Just so you know, It is not uncommon for new sensors to be no good! They are mass assembled and no checked for working.
When I use my generic ODB2 scanner the voltage for both varies and occasionally the voltage stays low for the rear sensor and that's when I think it triggers the lean alert.
They all look corroded from here!
You need to clean everything to bare metal on the body parts.
The nested one on the fender looks like crap too!
This is a common issue!
They all look corroded from here!
You need to clean everything to bare metal on the body parts.
The nested one on the fender looks like crap too!
This is a common issue!
Final had a chance to take everything apart and they were surprising clean but I used my Dremel w/ abrasive bit and cleaned everything up to nice shiny metal. Wanted to use a star lock washer but didn't have the correct size but it's all nice and clean.
Took the distribution block apart but it's completely covered in waterproofing sealant (think door panel sealant) so I wasn't able to take it apart but water tight and all the connections look clean.
BTW disconnected the battery while I was going this.
Put it altogether together, cleaned the battery terminals while I was at it and started the car and the MIL is still on.
Hopefully they light turns off in the drive to work.
Final had a chance to take everything apart and they were surprising clean but I used my Dremel w/ abrasive bit and cleaned everything up to nice shiny metal. Wanted to use a star lock washer but didn't have the correct size but it's all nice and clean.
Took the distribution block apart but it's completely covered in waterproofing sealant (think door panel sealant) so I wasn't able to take it apart but water tight and all the connections look clean.
BTW disconnected the battery while I was going this.
Put it altogether together, cleaned the battery terminals while I was at it and started the car and the MIL is still on.
Hopefully they light turns off in the drive to work.
Reset the MIL and drove over 100 miles and the light is still on. Guess it's not a ground fault. Actually the MIL turned back on as soon as I started the car so I think it's still electrical just not a ground fault.
Beware of the false prophets, they said. Anyone who jumps to quick conclusion the cause is likely ground fault gives bad advice unless there is compelling evidence suggests it, like signs of water damage or salt induced corrosion. Why? If you mess with otherwise intact connections you tend to compromise them. Modern cars electrical systems are very good and poor contact generally are caused by bad mechanics home or professional. The fault code suggests it is the downstream O2 sensor. Of course you can never rely literally on what the fault code tells you. Systematic debug is the only way to avoid chasing down the wrong rabbit holes.
Beware of the false prophets, they said. Anyone who jumps to quick conclusion the cause is likely ground fault gives bad advice unless there is compelling evidence suggests it, like signs of water damage or salt induced corrosion. Why? If you mess with otherwise intact connections you tend to compromise them. Modern cars electrical systems are very good and poor contact generally are caused by bad mechanics home or professional. The fault code suggests it is the downstream O2 sensor. Of course you can never rely literally on what the fault code tells you. Systematic debug is the only way to avoid chasing down the wrong rabbit holes.
Found a mechanic that's willing to look into the cause. Explained everything I've done so far and he agrees it's an electrical issue. Soon as the code was reset it popped back up as pending. So while I get my money together for the troubleshooting, I'm going to try swapping the sensors. After all I've got nothing to lose as my final DIY attempt. It just won't happen this weekend with the record highs!
Thanks Wayne. I'll check it out this weekend.
As for the O2 sensor I replaced them both with Nipo-Denso but the code remains.
Thanks again, let you know how it goes.
I am not aware of Nipo-Denso. If you read extensively here you would find that the consensus is the only one you want is NTK/NGK that is OEM for Gen 1. Did you keep the old ones? If so you might try to swap the upstream/downstream to see what happen. You should not rule out other causes of the engine or a cylinder running lean too. Assuming a ground fault from the get go is a bit of a leap.
I'm in the same boat. Suspected it's not the sensor since the P2096 comes back after clearing before I even start the car. Changed the O2 anyway but still the same. Did you find the issue?
I'm in the same boat. Suspected it's not the sensor since the P2096 comes back after clearing before I even start the car. Changed the O2 anyway but still the same. Did you find the issue?
Unfortunately no. Found a mechanic that's highly recommended so getting my money together to drop it off.
I'll update once he gets a thorough look at.
The voltage dropping suddenly on the downstream sensor sure sounds like a connection issue to me. Could be anywhere in the wiring harness though, not necessarily any of the grounds.
The voltage dropping suddenly on the downstream sensor sure sounds like a connection issue to me. Could be anywhere in the wiring harness though, not necessarily any of the grounds.
Yes. I know it feeds into the ECM but haven't found a good diagram of where the wiring routes to. It can't be too far since the ECM is right there but the wiring is all underneath it.
One thing to check is the grounding wire on the passenger side of the engine. both ends should be removed and cleaned (both wire and attachment points)
The large wire attached to the motor mount and the chassis.
Finally took the car to the mechanic and after checking for 3 weeks he's convinced it's the ECU.
Is there anyway to verify that it is the ECU? I googled ECU repair shops and one place recommended that I just purchase a used ECU and have it programmed. Tired of just buying parts that don't need replacing, it's getting very expensive!
Any recommendations on what I should do?
Downloaded INPA. Get the correct hookup. Reset your fuel adaptations. An all other adaptations that are showing up Once you do that. Your problem will be corrected. You car still thinks the old sensor is still there. You can run the car for a while. It will figure out to correct fuel adaptations. Or just use INPA.
