Fault codes on Voyager 89 TBI, autm

Hi all,
My Plymouth Voyager 89, TBI, 3 autm. speed, 170k KM has the next fault
codes: 15, 52 (I put the code description below)
For code 15: I don't know what should I check. My speedometer show
normal speed when running, the odometer also works fine. What else
should I check?
For code 52: I replaced the oxygen sensor with a new one, but the code
is still there. I check rust on catalytic converter (Note #5) but
nothing important. Indead, when engine is cold, run crummy. After
become normal temperature, the engine run well, but the code still
display when I stop and check the code.
Please any comments will be welcome.

Thanks, Chris
Montreal, CA


15 No speed/distance sensor signal
52 Oxygen sensor stuck at rich position (SEE NOTE #5!)
OR
52 Internal logic module fault ('84 turbo only)
NOTE #5.Wade Goldman wrote: In my case, the breather tube leading into
the catalytic converter had rusted and become detached. This some how
would cause the sensor to read an over rich condition and run crummy.
I did not trust the reliability of the weld over a corroded surface
and opted for the more expensive route of replacing the converter,
breather tube and all.

 

The reason your speedometer/odometer reads correct in spite of
the distance sensor fauly is because on your model year vehicle,
the speedometer/odometer is driven by a cable. This precludes a
problem with the distance sensor and/or associated wiring and
computer circuits. Odds are it is only a failed distance sensor.

Because a code 52 means that your engine is running too rich, fix
the cause of the rich fuel mixture.

 

Because a code 52 means that your engine is running too rich, fix

Thanks for reply.
What should I check first myself in order to find the cause, before to
go to a garage.
The cars symptoms are:
When start in cold wheather (-20, -30C here at Montreal), the car
starts well (fist shoot) but initial is running crummy (3-5 min.)
But when the engine become normal temp. is running well, not stalling,
not smoke, normal power.

Thank you again,
Cristian