Subaru Legacy 2002 Service Manual page 3212

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC) (RHD
MODEL)
HVAC System (Auto A/C) (Diagnostics)
11. Diagnostic Procedure with Diagnostic Trouble Code (DTC)
(RHD Model)
S001810
A: DTC 21 OR –21 (IN-VEHICLE SENSOR)
S001810K30
TROUBLE SYMPTOM:
When turning AUTO switch to ON, blower fan speed, outlet port and inlet port is not changed.
NOTE:
If DTC 21 or –21 appears on the display, replace the A/C control module. The in-vehicle sensor is built into
the A/C control module and cannot be replaced as a single unit.
AC-69