TROUBLE SHOOTING
SELF-DIAGNOSTICS
An Electronic Control Unit (ECU) within A/C-heater control
panel monitors system circuits and stores trouble codes in memory if
problems are detected. All codes, except Codes 22 and 23, are stored
in memory. Malfunction is current if Code 22 or 23 is displayed. To
retrieve stored codes, see RETRIEVING CODES. Codes are displayed at
temperature display. See Fig. 2.
RETRIEVING CODES
1) Simultaneously press and hold AUTO and recirculated air
switches. See Fig. 2. Turn ignition on. All indicators will flash 4
times, at one-second intervals. Tone will sound when indicators flash.
2) A/C system will enter self-diagnostic mode. To end
indicator check, press and release OFF switch. Read codes at
temperature display.
3) If trouble code is displayed, proceed to appropriate
trouble shooting procedure. See DIAGNOSTIC CODE IDENTIFICATION table.
Codes are displayed in ascending order. To slow rate at which codes
are displayed, press fresh air button to change display to step
operation. Each time fresh air button is pressed, display changes by
one step.
4) If tone sounds as code is displayed, problem currently
exists. If tone does not sound as code is displayed, problem occurred
in past and does not presently exist.
Code Diagnosis
00 ................................................ Normal
11 (1) ............. In-Vehicle Temperature Sensor Circuit
12 (2) ................ Ambient Temperature Sensor Circuit
13 ................. Evaporator Temperature Sensor Circuit
14 .................... Coolant Temperature Sensor Circuit
21 (3) .............................. Solar Sensor Circuit
22 (4) .................... Compressor Lock Sensor Circuit
23 (4) ........................... Pressure Switch Circuit
31 .................. Air Mix Door Position Sensor Circuit
32 ................ Air Inlet Door Position Sensor Circuit
33 ............... Air Outlet Door Position Sensor Circuit
41 ....................... Air Mix Door Servomotor Circuit
42 ..................... Air Inlet Door Servomotor Circuit
43 .................... Air Outlet Door Servomotor Circuit
(1) - If in-vehicle temperature is -4 F (-20 C) or less,
Code 11 may set even though system is normal.
(2) - If outside air temperature is -58 F (-50 C) or less,
Code 12 may occur set though system is normal.
(3) - If testing is done in a dark area, Code 21 may set
even though system is normal. Shine a light at solar
sensor and recheck codes.
(4) - Malfunction is current. Code is not stored in memory.
ACTUATOR CHECK
1) Perform step 1) of RETRIEVING CODES. When system enters
self-diagnostic mode, press recirculated air button. Each mode door,
motor, and relay will operate at one-second intervals. Press fresh air
button to display codes one at a time, and perform step-by-step
actuator check.
2) Check airflow and temperature by hand. Tone will sound
each time display code changes. Each display code is associated with a
system operating condition. See Fig. 3 or 4. Press OFF button to
cancel actuator check mode.