1996 850 EGR p0402 any fixes ?

jetmecanic · Post by **jetmecanic** » 22 Apr 2014, 15:52

Hello all. New to the site. Have a question about an egr issue. CEL light on p0420. Cleaned egr and replaced vacuum lines. Still getting p0420 code after approx 3 drive cycles. Car does have a aftermarket MAF. If it weren't for required emissions I would let it ride. Any ideas? Any way to test the egr controller?
Thanks in advance

Post by **JDS60R** » 22 Apr 2014, 16:17

P0420 is a catalyst efficiency code. Usually related to a failed cat from lack of maintenance on replacing A/F ratio sensors ( Oxygen sensors, MAF and coolant temp sensor). Search the database here and you will find tons. If I remember your model does not like aftermarket MAF sensors.

Hit the cat from below and see if it is broken up, if not get a temp reading on the front weld bead and the rear. The rear should be 300 degrees F higher if the catalyst is functioning on a warmed up car.

Please refer to forum rules on using All caps or Help in title. You agreed not to when signing up.

jetmecanic · Post by **jetmecanic** » 22 Apr 2014, 16:24

JDS60R
My bad. Wont happen again. Made a typo on the title. The code is p0402 not p0420.

Post by **JDS60R** » 22 Apr 2014, 16:43

no problem

Possible help

https://www.matthewsvolvosite.com/forums ... =1&t=26511

http://volvoforums.com/forum/volvo-s60- ... ode-19974/

http://www.datsc.com/tabid/122/OBD-Erro ... fault.aspx

jetmecanic · Post by **jetmecanic** » 07 May 2014, 11:31

Quick thanks and update. Replaced all vacumn hoses and all checked good. Thanks all!!!

Post by **matthew1** » 07 May 2014, 11:45

Thanks for the followup.