Entering Self-Diagnostics
Ensure engine temperature is greater than 104°F (40°C). Depress auto amplifier OFF and AUTO switches simultaneously and turn ignition on. Auto amplifier will enter DIAGNOSTIC STEP 1. See DIAGNOSTIC STEP 1 .
Exiting Self-Diagnostics & Clearing Trouble Codes
To exit self-diagnostics, system must be in DIAGNOSTIC STEP 2. Turn ignition off. To clear trouble codes, depress auto amplifier OFF and DEF switches simultaneously and turn ignition on. AUTO switch LED and -88 in temperature display will flash 3 times. All trouble codes are now cleared and system will exit self-diagnostics.
Display Indicator Inspection
- Indicator lights should be on and temperature display should indicate -88 (all segments on). (Scheme 2)
- If indicators are not on, or temperature display does not indicate -88, check auto amplifier power supply and ground circuits. See «A/C SYSTEM OR SELF-DIAGNOSTICS INOPERATIVE»(ref-36837-S24660946742001010900000). If indicator lights and temperature display segments are okay, after approximately 9 seconds, self-diagnostics will proceed to DIAGNOSTIC STEP 2.
Scheme 2
Sensor Circuit & Door Motor Inspection
- If a malfunction has occurred in a monitored circuit, temperature display will indicate a trouble code. If monitored circuits are functioning properly, temperature display will show "00" indicating no system malfunctions. See «SENSOR CIRCUIT TROUBLE CODES»(ref-36837-S15921316492001010900000) table.
- If a trouble code is indicated, proceed to appropriate code testing procedure under TESTING. If all sensors are okay (Code 00 displayed), depress AUTO switch to proceed to DIAGNOSTIC STEP 3 or depress DEF for a minimum of 4 seconds to proceed to DIAGNOSTIC STEP 4. Diagnostic step 3 checks A/C output components. Diagnostic step 4 is used to adjust display temperature.
| Code No. | Diagnosis |
|---|
| 00 | No Malfunctions |
| 11/21 | Open/Short In In-Vehicle Sensor Circuit |
| 12/22 | Open/Short In Ambient Sensor Circuit |
| 13/23 | Open/Short In Sunload Sensor Circuit |
| 14/24 | Open/Short In Evaporator Sensor Circuit |
| 15/25 | Open/Short In Refrigerant Temp. Sensor Circuit |
| 16/26 | Open/Short In Water Temp. Sensor Circuit |
| 31 | Faulty Air Mix Door Motor Circuit |
| 32 | Faulty Mode Door Motor Circuit |
| 33 | Faulty Air Mix Door Motor Circuit |
| 34 | Faulty Mode Door Motor Circuit |
| 35 | Faulty Intake Door Motor Circuit |
| (1) If malfunction is currently occurring, code will be circled in the display. |
| (1) | If malfunction is currently occurring, code will be circled in the display. |
SENSOR CIRCUIT TROUBLE CODES (1)
Actuator Inspection
- Temperature display should read 41. Check compressor and blower operation and positioning of mode door motor, intake door motor and air mix door motor. See «ACTUATOR OPERATION SPECIFICATIONS»(ref-36837-S32753611062001010900000) table.
- To advance to next code, press DEF switch. Ensure all actuators operate as specified. If any actuators DO NOT function as specified, test appropriate circuit under TESTING.
| Actuator | Test Results |
|---|
| Code 41 |
| Mode Door | Defrost |
| Intake Door | Fresh/Recirculation |
| Air Mix Door | Full Hot |
| Blower Motor | 5 Volts |
| Compressor | On |
| Compressor Solenoid | Zero Amps |
| Code 42 |
| Mode Door | Heat |
| Intake Door | Fresh |
| Air Mix Door | Full Hot |
| Blower Motor | 7 Volts |
| Compressor | On |
| Compressor Solenoid | .65 Amps |
| Code 43 |
| Mode Door | Bi-Level |
| Intake Door | Fresh |
| Air Mix Door | 50% Hot |
| Blower Motor | 11 Volts |
| Compressor | Off |
| Compressor Solenoid | Zero Amps |
| Code 44 |
| Mode Door | Vent |
| Intake Door | Fresh |
| Air Mix Door | Full Cold |
| Blower Motor | Fan High |
| Compressor | Off |
| Compressor Solenoid | Zero Amps |
| Code 45 |
| Mode Door | Vent |
| Intake Door | Recirculation |
| Air Mix Door | Full Cold |
| Blower Motor | Fan High |
| Compressor | Off |
| Compressor Solenoid | Zero Amps |
ACTUATOR OPERATION SPECIFICATIONS
TESTING
| WARNING | To avoid injury from accidental air bag deployment, read and carefully follow all SERVICE PRECAUTIONS and DISABLING & ACTIVATING AIR BAG SYSTEM procedures in in the AIR CONDITIONING & HEAT section AIR BAG RESTRAINT SYSTEM article in ACCESSORIES & ELECTRICAL section. |
A/C AUTO AMPLIFIER PIN VOLTAGE TEST
Remove A/C amplifier to gain access to connectors. See AUTO AMPLIFIER under REMOVAL & INSTALLATION. With wiring harness connected to A/C amplifier, ensure voltages are as specified. Connect voltmeter between specified terminal(s) and/or ground.
See A/C AUTO AMPLIFIER PIN VOLTAGE TEST (16-PIN CONNECTOR) and A/C AUTO AMPLIFIER PIN VOLTAGE TEST (20-PIN CONNECTOR) tables. If voltage is not as specified, check appropriate circuit and input/output device. Repair or replace as necessary. If circuit and input/output device are okay, replace A/C amplifier.
| Circuit & Test Condition | Voltage |
|---|
| A/C Relay |
| Terminal No. 12 (Brown Wire) To Ground | (1) Battery |
| Air Mix Door Motor (PBR) |
| Terminal No. 5 (Green/Black Wire) To Terminal No. 6 (Green/Yellow Wire) | (2) Battery |
| Auto Amplifier Ground Circuit |
| Terminal No. 16 (Black Wire) To Ground | Zero |
| Hi Relay |
| Terminal No. 12 (Yellow/Green Wire) To Ground | (3) Battery |
| Ignition Power Supply |
| Terminal No. 2 (Green/Red Wire) To Ground |
| Ignition On | Battery |
| Engine Running | 13-14 |
| Memory Back-Up (Battery Voltage) |
| Terminal No. 1 (Blue/Red Wire) To Ground | (4) 13-14 |
| Mode Door Motor |
| Terminal No. 3 (Green/Red Wire) To Terminal No. 4 (Light Green/Black Wire) | (5) Battery |
| Off Relay Terminal No. 12 (Blue/Black Wire) To Ground |
| Terminal No. 12 (Blue/Black Wire) To Ground | (4) Battery |
| (1) Ignition and A/C switches on. (2) With ignition on, voltmeter positive lead at terminal No. 5 and negative lead at terminal No. 6 and temperature set at 65°F (18°C). Battery voltage should also be present with voltmeter positive lead at terminal No. 6 and negative lead at terminal No. 5 and temperature set at 85°F (32°C). (3) With ignition on. (4) Voltage specified is with engine running. (5) With ignition on, voltmeter positive lead at terminal No. 3 and negative lead at terminal No. 4 and VENT switch depressed. Battery voltage should also be present with voltmeter positive lead at terminal No. 4 and negative lead at terminal No. 3 and DEF switch depressed. |
| (1) | Ignition and A/C switches on. |
| (2) | With ignition on, voltmeter positive lead at terminal No. 5 and negative lead at terminal No. 6 and temperature set at 65°F (18°C). Battery voltage should also be present with voltmeter positive lead at terminal No. 6 and negative lead at terminal No. 5 and temperature set at 85°F (32°C). |
| (4) | Voltage specified is with engine running. |
| (5) | With ignition on, voltmeter positive lead at terminal No. 3 and negative lead at terminal No. 4 and VENT switch depressed. Battery voltage should also be present with voltmeter positive lead at terminal No. 4 and negative lead at terminal No. 3 and DEF switch depressed. |
A/C AUTO AMPLIFIER PIN VOLTAGE TEST (16-PIN CONNECTOR)
| Circuit & Test Condition | Voltage |
|---|
| Accessory Power Supply Terminal No. 18 (Light Green/Red Wire) To Ground |
| Engine Cranking | Zero |
| Engine Running | Battery |
| Air Mix Door Motor (PBR) Terminal No. 14 (Black/White Wire) To Terminal No. 11 (Green/Black Wire) | (1) About .5 |
| Ambient Sensor Terminal No. 2 (White/Green Wire) To Terminal No. 11 (Green/Black Wire) | (2) About 5 |
| Evaporator Sensor Terminal No. 3 (Black/Yellow Wire) To Terminal No. 11 (Green/Black Wire) | (2) About 5 |
| Illumination Control Signal Terminal No. 10 (Red Wire) To Ground | (3) Battery |
| Mode Door Motor (Fresh Voltage) Terminal No. 7 (Green/White Wire) To Terminal No. 11 (Green/Black Wire) | (4) Battery |
| Mode Door Motor (PBR) Terminal No. 15 (Light Green/Black Wire) To Terminal No. 11 (Green/Black Wire) | (5) About 4.5 |
| Mode Door Motor (REC Voltage) Terminal No. 5 (Green Wire) To Terminal No. 11 (Green/Black Wire) | (6) Battery |
| Refrigerant Temperature Sensor Terminal No. 4 (Yellow/Blue Wire) To Terminal No. 11 (Green/Black Wire) | (2) About 5 |
| Sensor Ground Circuit Terminal No. 11 (Green/Black Wire) To Ground | Zero |
| Sunload Sensor Terminal No. 13 (White/Blue Wire) To Terminal No. 11 (Green/Black Wire) | (2) About 5 |
| Sensor Voltage Terminal No. 1 (Blue/Red Wire) To Ground | (7) Zero |
| Water Temperature Sensor Terminal No. 12 (Blue/White Wire) To Terminal No. 11 (Green/Black Wire) | (2) About 5 |
| (1) With temperature set at 65°F (18°C) and AUTO switch on. Voltage reading of 4.5 volts with temperature set at 85°F (29°C). (2) With ignition on and sensor connector disconnected. (3) With ignition and light switches on. (4) With ignition and DEF switches on. (5) With ignition and VENT switches on. Voltage reading should be .5 volt with ignition and DEF switches on. (6) With ignition and CIRC switches on. (7) With ignition on, voltage reading should be 5 volts. |
| (1) | With temperature set at 65°F (18°C) and AUTO switch on. Voltage reading of 4.5 volts with temperature set at 85°F (29°C). |
| (2) | With ignition on and sensor connector disconnected. |
| (3) | With ignition and light switches on. |
| (4) | With ignition and DEF switches on. |
| (5) | With ignition and VENT switches on. Voltage reading should be .5 volt with ignition and DEF switches on. |
| (6) | With ignition and CIRC switches on. |
| (7) | With ignition on, voltage reading should be 5 volts. |
A/C AUTO AMPLIFIER PIN VOLTAGE TEST (20-PIN CONNECTOR)
In-Vehicle Sensor Resistance
- Turn ignition off. Remove auto amplifier. See «AUTO AMPLIFIER»(ref-36837-S38635828832001010900000) under REMOVAL & INSTALLATION. Disconnect in-vehicle temperature sensor 2-pin connector. (Scheme 3) Check resistance between sensor connector terminals. See IN-VEHICLE TEMP. SENSOR RESISTANCE SPECIFICATIONS table.
- If resistance reading is not as specified, replace sensor. If resistance reading is okay, turn ignition on. Measure voltage available to in-vehicle sensor. If approximately 5 volts is not available to sensor, check wiring harness between in-vehicle sensor and auto amplifier.
- Repair wiring harness as necessary. If wiring harness is okay, replace auto amplifier. If approximately 5 volts is available to sensor, an intermittent problem may exist. Ensure auto amplifier connectors are properly connected to auto amplifier.
Scheme 3
| Temperature °F (°C) | Ohms |
|---|
| 4 (-20) | 16,500 |
| 32 (0) | 9930 |
| 50 (10) | 6000 |
| 68 (20) | 3750 |
| 77 (25) | 3000 |
| 86 (30) | 2420 |
| 104 (40) | 1060 |
IN-VEHICLE TEMP. SENSOR RESISTANCE SPECIFICATIONS
