# P0400, P0136



## smourning2666 (Mar 23, 2011)

My service engine light came on due to codes P0400 and P0136. After troubleshooting i found a broke hose on the EGR which i replaced. I cleared the codes expecting the light to return with a P0136. I've driven 120mi over a couple trips/days and still no light. Was the O2 sensor problem caused by the EGR problem? Has fixing one problem solved the other?


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## jdg (Aug 27, 2009)

Broken hose on the EGR (I'm assuming it was a vacuum line) equals vacuum leak.
Vacuum leak = lean running
Lean running = low voltage on the O2 sensor that the computer may or may not be able to compensate for.
Low voltage on the O2 sensor output = P0136.
Fix the hose, no more vacuum leak, no more lean mixture, no more low voltage, no more code.


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## smourning2666 (Mar 23, 2011)

Thank you. I appreciate you taking the time to explain.


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## jdg (Aug 27, 2009)

Keep in mind, it's only a theory.
Could also be just plain luck 
For all I know, I'm so far out in the weeds, I'm outstanding in the field (get it? in the weeds, outstanding in the field...ok...I'm done.)
Good luck at any rate...


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