Hello again:
I've looked through all the threads and would like some further input. My amber "check engine" came on a few weeks ago. I lubricated the gas cap o-ring and cleared the code. Two weeks later the check engine light came back and coded ECM431A (leak diagnostic unit, pump). My trusted mechanic suggested replacement. He did not have one in stock and quoted about $260 USD. He suggested it was no big deal and if you didn't mind the light; carry on!

. My question is this. Should I update the software first to see if that works or go right to the replacement ? I've got a 2005 V70

Thanks again, Mike

 

That code is stored if the pump uses too much current during that portion of the drive cycle. Could be because there is a leak. But- when the pumps get old - they use more current or stop working properly. A smoke test would be a good idea to make sure there are no leaks prior to pump or software replacement.

The new software uses a different test method to determine vapor leaks and if the pump is good MIGHT prevent a code.

Updating the software can cost as much as replacing the pump - most of my customers choose to replace the pump to solve the problem. For your car after 15 years the pump is probably bad.

So there may not be anything wrong - there may not be a vapor leak in the tank system - and it's true if you don't need an emission inspection and can stand the warning light you can ignore it. If there is a vapor leak it's as harmful as leaving your gas cap slightly loose. ( I'm not advocating polluting or ignoring/modifying any anti pollution device.)

 

Hi Hoonk:

Probably a final note here. I cleared the codes and there was no light for a few months. It reappeared about a month ago then disappeared after a couple of short drives. All seems okay,

cheers, Mike