Oregon Scientific THT 312 Thermometer/clock outside temp stuck "LL.L" -- won't reset

1. Take the cover off the back of the remote sensor.
2. Set the chanel to ch.1. (I tried all three but only ch.1 worked for me).
3. Use a stick, needle, what ever you can (but you need two) and hold down the reset button on both the sensor and the clock at the same time.)

If done right, it should only take a few seconds to start.
The outside temp is delayed at first. Be patient.

http://www2.oregonscientific.com/ulimages/manuals2/THT312.pdf

Choose the appropriate model from
http://www2.oregonscientific.com/service/manual_downloads.asp?t=3&cid=2

I have the same unit (IWA-80055) and after not finding anything helpful on the net, I just messed with it until I got it fixed. Here's what to do:

1. Take the cover off the back of the remote sensor.

2. Set the chanel to ch.1. (I tried all three but only ch.1 worked for me).

3. Use several tools. (i.e. a stick, needle, what ever you can but you need two) and hold down the reset button on both the sensor and the clock. (at the same time.)

If done right, it should only take a few seconds to start.

The outside temp is delayed at first. Be patient.

How are the batteries in the remote unit. Is it or the terminals corroded in any way?

http://www2.oregonscientific.com/ulimages/manuals2/RMR616HGA.pdf

Actually I just kept working with it, but I did put a new battery in and that may have helped. It is working fine now, thanks for your response.

Two things...
1) press reset on the base unit
2) press and hold for 2-3 seconds the channel button

You should be in business

Have you got this solved?

I've had a similar problem with another model, an Oregon Scientific Model IWA-80055 Wireless Thermo Clock, in which when I replaced the batteries in the remote sensor, the clock would not read the temperature from the remote sensor.
I found it fairly consistent to solve this by taking a battery out of place in the clock and putting it back in.  Unfortunately this also messed up the clock's time and date.  This is also in the instructions catalogue for the device, check and see if yours gives a similar solution.