SELF DIAGNOSIS PROCEDURE
When the ACC temperature control display starts flashing, it is telling you that the system has a fault. You may be a little low on Freon, or you could have other problems. Use the procedure below, to see if you can retrieve the codes. After resetting the codes, the compressor should cycle on long enough to do a pressure test. If not, try disconnecting the battery negative cable for about 30 sec. That will clear any residual memory from the ACC & PCM.
This procedure will work on 1992 -1993 models with ACC, and may also work on 1988-1991 models. (And my work for later years as well).
The diagnostic mode also contains a data list mode and an override mode.
Be careful not to select modes 01 or 02, as these are different modes, and may cause problems.
If you suspect you are in the wrong mode, press OFF repeatedly until you exit to normal mode. If the temperature display flashes for 2 minutes when the ignition is turned to RUN, a trouble code is set.
1. Turn ignition to RUN. Press OFF and WARM (temperature up) buttons simultaneously. (Hold in buttons until flashing segment test begins).
2. Watch the segment test, then the trouble codes will be displayed.
3. Code Key:
00 - No codes
10 or 110 - Ambient Temp Sensor circuit open or shorted.
13 or 113 - In-Vehicle Temp Sensor circuit open or shorted.
15 or 115 - LH Solar Sensor circuit open or shorted.
35 or 135 - Data Line failure - HVAC Control Assembly
38 or 138 - Data Line failure - PCM
40 or 140 - Driver Air Mix Motor circuit open or shorted, or not calibrated
48 or 148 - Long Term Freon Loss
52 or 152 - Keep Alive Memory lost; sets with battery disconnected
66 or 166 - Low Freon
A number 1 prefix indicates a history trouble code!
4. Press OFF twice once the codes are displayed to end diagnostic mode, OR to clear trouble codes, press FAN DOWN three times (make sure 03 is displayed).
Once 03 is displayed, press FAN UP to clear trouble codes. Then repeatedly press OFF to end diagnostic mode.
Last edited by mellowde; 02-27-2015 at 10:53 AM.