Volvo 850''s: evil ground causing problems?

Post by **JimBee** » 20 Aug 2013, 04:41

This is another tidbit from ipdusa site:

Sunday, July 17, 2011 - MARTYN P ROWSON
I have worked in Volvo dealers for the passed 18 years and experienced a lot of customers with 850, C,S,V70 with 10valve and 20 valve engines engine light on. Fault codes say MAF,boost pressure sensor,baro sensor and long term fuel trim faults. 90 of the time the fault is a dirt or loose earth point under the right head lamp. I remove the lamp, move the front panel to access the earth terminal, grind away the paint and replace the bolt. Also found it improved startying and performance.

http://www.ipdusa.com/blogs/105/top-10- ... v70-models

I'm not aware of this ground. Does anybody have additional information?

Post by **jblackburn** » 20 Aug 2013, 07:04

I didn't know there was one over there, but my guess is that it's the major ground point for the entire ECU box.

Good to know! Thanks!

Post by **northernlights** » 20 Aug 2013, 07:31

I suspected a grounding problem on this post, although it may not have been the case. This was for a 99 V70, but there was a main ground point near the right side headlight.

https://www.matthewsvolvosite.com/forums/viewtopic.php?t=52657#p263626

From what I've seen, auto sensors are very sensitive to bad grounds because most of the signals are voltage based. Bad grounds mess up the signals as they 'use up' some of the voltage.