2001 s40 trouble codes

geeman · Post by **geeman** » 07 Nov 2008, 09:52

i have a 2001 s40 with trouble codes po133 and po128 what do i need to do

Post by **billofdurham** » 07 Nov 2008, 12:02

Welcome to Matthew's Volvo Site.

It is possible that the codes are linked.

P0128 is a faulty engine thermostat. Replace it.

P0133 is the front heated oxygen sensor which sends information to the ECU about the fuel/air mixture. As the thermostat is faulty the information will inaccurate. This fault may rectify itself when you replace the thermostat.

Bill.

Post by **billofdurham** » 16 Nov 2008, 12:25

I have received the following in a pm from geeman. I am adding this to the topic as it is of general interest.

I was getting two codes. I changed my thermostat as suggested that code is cleared. I was still getting po133. I changed my o2 sensor but I am still getting code po133 and now also po107. what do I need to do next

P0133 is a slow response from the O2 sensor which may be a fault in the wiring. Have you checked the wiring is properly connected?

P0107 is the Manifold Absolute Pressure (MAP) sensor/Barometric Pressure (BARO) sensor low input. The probable cause is a wiring short to earth (ground) at the sensor or the ECM.

Bill.