Check engine light

#1

I have a 2002 Volvo S40 with about 62,000 miles. The check engine light first came on 2 mos. ago and at that time, I changed the gas tank cap, which the Auto Zone Computer said. The light stayed off for about 2 mos. and then back on. Went back to Auto Zone and this time code indicated low cooent, replace sensor or replace thermostat. Coolent was ok and wasn’t overheating and getting adequate heat, etc. As a matter of eminiation I had the sensor replaced. Light stayed off for 1 days and is now back on…any suggestions?

#2

How about getting the actual error codes? They should be in the format [P0123]

#3

I think it was P0128

#4

If it was P0128, here is a pretty good discussion of it:

It would be good to get the actual coolant temp checked (rather than relying on gauge and heat level), and make sure that your cooling fan isn’t stuck on.

#5

Thanks so much for post…I’m having the thermostat replaced next week. We’ll see.