Hi Tim,

We too have a '93 240 wagon (Classic edition).  Had it since new.
I would first re-clean the AMM plug's pins and sockets *thoroughly* with
electrical contact cleaner, then apply dielectric grease and push and pull
the plug in and out ten times.  ( If that seems a little weird do it anyway.
I got that from a Volvo technician .......)

You don't mention any drivability problems with the engine.

My info on Diagnostic Code 3-2-2 for the 240 LH2.4 Fuel Injection confirms
your "AMM burn-off signal fault", but the report (from brickboard.com) adds
that the cause is "a wiring break between FI terminal 8 and AMM #4".  (I
feel that could still mean the AMM plug needs cleaning.)  The report also
states that the symptoms are "various driving problems due to the dirty AMM
wire", and the Check Engine light does not come on for this fault

Re the 1-1-3 code, the Check Engine light does come on, and the fault is
"Fuel Trim (Lambda control) too lean OR RICH".  The cause is "mixture
incorrect (duh!........); O2S wiring fault."  The symptom is "high fuel
consumption".

Hope this is of some help.
Good Luck.
Andy I.

The 322 code does NOT set the check engine light.  Something else caused it
to come on the first time and the mechanic either missed it or did not pull
enough codes.  The no charge option could be  an easy way to get you back
because he MAY know what is going on but can make more money on a new AMM
than fixing what is really wrong. ( Note: the last statement is from an
individual who treats everything as the sky is falling and everybody is out
to get me before the whole story has evolved.)

The 113 does set the check light.  But, before spending any money, clean the
contacts to the AMM like Andy indicates...not too much effort and will do a
lot of good and no harm unless you break or bend something.  See, the sky is
falling...:>)

AND then...there are two ten mm bolts with wires under them on the intake
manifold.  Loosen them, clean them and retighten them.  Also, clean the
battery terminals and be sure the wires to them are clean and tight.

Then clear your codes.  If any codes return after the above cleaning, then
you should be concerned.

Those two bolts and wires provide ground for all the fuel control components
and are also the reference ground point for the Fuel Control Computer (ECU)
to "self diagnose" and set codes if something is wrong.

The manifold is aluminium, the wire's washer is some coated brass metal, and
the bolt is treated steel.  Combine those three differences with electricity
and corrosion will occur if the connection is not tight all the time.  With
the different metals, cold and heat extremes ( winter driving in a nutshell)
will loosen the contact enough to cause problems over time.

Every Vovlo Green Factory Service manual relating to fuel and emission
issues begins with a bold statement to Clean and verify grounds and
eliminate vacuum leaks prior to any testing of components.

Duane

PS.  The time to clean those is just after a drive long enough to heat
things up under the hood.  The residual heat helps keep your fingers warm in
the cold weather.