Hello,

I'v had my check engine light on for a while now, and after reading the error codes, I'm getting the codes P0401 which is EGR flow insufficient P0136 which is O2 sensor circuit malfunction (Bank 1 Sensor 1). Is my faulty EGR valve causing the O2 sensor issue? or is there something else wrong?

Thanks for any help you can give

 

two different problems . for the P0136 more the likely is a bad O2S sensor. need to be able to read live engine data to confirm the problem but on most cases is a lazy sensor causing this code , for the P0401 the best way to determinate if egr valve work is applied vacum to it when engine is at idle, a good egr flow will shut down the engine wild doing this ,(it means egr flows ) if engine dost't shut of ,possible problems bad egr valve , clogged egr tubes .If engine shuts off on this test ,problem is on the activation side of the egr system ,posible problems /egr vsv ,torn or clogged egr system vacum hose ,bad vacuum modulator valve, no vacum ,ecm .

 

The P0401 code means that OBD detected an insufficient amount of EGR.
P0136 means the O2 oxygen sensor's voltage remained low for longer than 2 minutes. This, is interpreted by the ECM as a low voltage condition and sets the MIL.
try to use a code scanner clear the fault codes.
this tool maybe can help you.

 

Okay, so I checked all the hoses on the EGR valve, all seem fine. I bought some Sea Foam to try to get some of the carbon out of it, however I am unable to get the damn valve off. Any ideas what size the bolts are that are holding it on? I've tried everything I have and can't get it. It's a 1999 with the 2.2 in it, not sure if that matters or not...

Oh, and I'm not sure what happened, or what I did, but the P0136 code is no longer an issue. At least not at this point in time.

Again, thanks for any help you can give.

 

The P0401 code means that OBD detected an insufficient amount of EGR.
A code P0136 may mean that one or more of the following has happened:

• Faulty O2 sensor leak in exhaust close to O2 sensor
• Short to voltage on O2 signal circuit
• Open in circuit resistance caused by corrosion in connector