Check engine light - need some assistance

'95 850 Turbo
190k miles
Check engine light came on
Noted occasional hesitation when starting and rough idle when first
started. Occurrences were random.
Diagnostics port A3
Code: 3-1-5 (EVAP system fault)

I need ideas as to where to start checking and what I need to be
looking for


TIA,

 

This is a guess. Could something be wrong with the evaporative
emission control system? Like the EVAP valve not opening or shutting
okay? That kinda ties in with the rough idle when first started, but
as I said, it is a complete guess -- so take it with a liberal heap
of salt.

Bev

 

by Steve Sharp dropped his wrench, scratched
his head and mumbled,

Typically the auxiliary air pump has sucked up enough water to cause the
motor to seize or destroy the relay or both. When you replace them
reroute the intake hose to prevent it from easily sucking in water.

Bob

 

A3 is ABS. My book doesn't list a code 3-1-5 for ABS, so assuming it's
really A2, fuel:
The problem can be a clogged charcoal cannister, EVAP hoses or a bad
valve. What happens is the EVAP valve is closed, and then when you're
at a stable idle at least 17 minutes after the car is started, the EVAP
valve is opened up. The computer then looks for some result of the
valve opening by monitoring the oxygen sensor. If opening the valve
doesn't make any changes to the fuel mixture, then the computer assumes
something is wrong and the code is set.