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(1998 Volvo V70)
in Centreville, VA on February 27, 2011

Frequent P0410 OBD2. (PAIR) Air pump run ok if relay manually
opperated.. Have also changed realy.. ECU fail to energise it... (ECU Energises Vacume soleniod okay sas valve opens)

Vacume soleniod operates ok and opens sas valve.

I am completely in the dark now.

Can the O2 sensors contribut to this dilema.?

Any Advice would be greatly Appreciated..

Displaying 1 answers & 3 comments
Popular Answer
on March 03, 2011
Hi Greg,
Can you check the emissions readiness status? Are you positive the ECU is not attempting to activate the pump during warm-up?
on March 03, 2011
Hi Bret..
Status is "Not Ready"
Voltage on one side of the Pump relay reads 13.4v .. The other side is 2.4 v measured
to ground... I reckon the ECU should take off the 2.4 volts and supply a
ground or low impedence connection for the pump relay to energise...

I am considering using the ground from the SAS vacume soleniod, as this energises
okay eveyrtime.. (am)\. It is just bugging and frustrating me to no end.. I got two 98 70's
suffering from this dilema. Hard to ignore CEL.

on March 14, 2011
Sorry I took so long to respond to this. Something just doesn't sound right. The way I always addressed these is with the Volvo Diagnostic tool that activates the air pump diagnostic test. Then I would monitor the air pump and the oxygen sensors to determine if the system was functioning properly.
Without being able to be there and perform tests it's hard to give much more advice. Is there a good Volvo shop that can help with this?
on March 14, 2011

Hi Bret...

Yesiree.. If I had Command Diagnostic it would be a welcome


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