I would like to thank this forum for expert assistance (VIA search) in resolving a recent problem with my 93 STS Seville that has been a real peach* up until recently.


Instrument Panel - key on - engine running:

Speedo went to top of range and back
Tach went up and down
Monitored Systems OK message appeared
Other items showed a key on initialization cycle
HVAC reset to 75 degrees on AUTO
Loss of mileage computation and range
I052 Error code SET

This devolved into the above with the addition of:

Engine Stall at idle
Restart not always available
I052 Error again
P091 Error (new) - due to engine stall in gear - not a new problem, just a symptom of the existing one

Thanks to you fine folks I investigated the RED battery cable.

Disconnected the battery (NEG first - Safety First of course )
and found the smaller gauge POS battery cable to have some corrosion.
Cleaned - sprayed anti-corrosion stuff - re-connected.

Problem Solved!

Many thanks. Drinks are on me.

PS - I had a clue early on:
At a stoplight, the lights would sometimes seem dimmer than usual. A check of the dashboard battery voltage often showed under 12.2 volts. Now even with the AC on and the radiator/condenser cooling fans on, it doesn't go below 12.9.

*OK , well I've replaced a motor mount per our local inspection station - they wanted $400 for the job (the big one underneath - did it myself)

Car now has 108,000 miles - I am the second owner- 1st owner was a very nice older couple residing in Florida that kept it garaged. Not a single ding on the doors when I bought it - now we have a half-dozen. Anyway - I can thank Grandma for the car.