1996 Lexus SC 400FACTORY OEM SERVICE PROCEDURE

Retrieving Codes

  1. Simultaneously press and hold AUTO and recirculated air switches. See Figure. 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.
DIAGNOSTIC CODE IDENTIFICATION

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.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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