Toyota 4Runner manuals

Toyota 4Runner: Problem Symptoms Table

PROBLEM SYMPTOMS TABLE

HINT:

  • Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.
  • Inspect the fuses and relays related to this system before inspecting the suspected areas below.
Air Conditioning System

Symptom

Suspected Area

See page

All functions of A/C system do not operate

Proceed to "IG Power Source Circuit"


Proceed to "Back-up Power Source Circuit"


Proceed to "Air Conditioning Control Panel Circuit"


Replace air conditioning amplifier assembly


LIN communication system


Air Flow Control: No blower operation

Proceed to "Blower Motor Circuit"


Proceed to "Air Conditioning Control Panel Circuit"


Replace air conditioning amplifier assembly


LIN communication system


Air Flow Control: No blower control

Proceed to "Blower Motor Circuit"


Proceed to "Air Conditioning Control Panel Circuit"


Replace air conditioning amplifier assembly


LIN communication system


Air Flow Control: Insufficient air flow

Proceed to "Blower Motor Circuit"


Replace air conditioning amplifier assembly


Temperature Control: No cool air comes out

Check volume of refrigerant


Check for refrigerant gas leak


Replace cooler expansion valve


Check cooler compressor assembly


Check No. 1 pressure switch


Proceed to "Air Conditioning Compressor Magnetic Clutch Circuit"


Proceed to "Compressor Lock Sensor Circuit"


Proceed to "Air Mix Damper Control Servo Motor Circuit (Driver Side)"


Proceed to "Air Mix Damper Control Servo Motor Circuit (Passenger Side)"


Proceed to "Room Temperature Sensor Circuit"


Proceed to "Ambient Temperature Sensor Circuit"


Proceed to "Evaporator Temperature Sensor Circuit"


Proceed to "Driver Side Solar Sensor Short Circuit"


Proceed to "Front Passenger Side Solar Sensor Short Circuit"


Proceed to "BUS IC Communication Malfunction"


Proceed to "Air Conditioning Control Panel Circuit"


Replace air conditioning amplifier assembly


LIN communication system


Temperature Control: No warm air comes out

Proceed to "Air Conditioning Control Panel Circuit"


Proceed to "Air Mix Damper Control Servo Motor Circuit (Driver Side)"


Proceed to "Air Mix Damper Control Servo Motor Circuit (Passenger Side)"


Proceed to "Room Temperature Sensor Circuit"


Proceed to "Ambient Temperature Sensor Circuit"


Proceed to "Driver Side Solar Sensor Short Circuit"


Proceed to "Front Passenger Side Solar Sensor Short Circuit"


Proceed to "BUS IC Communication Malfunction"


Replace air conditioning amplifier assembly


LIN communication system


Temperature Control: Output air is warmer or cooler than set temperature or response is slow

Check volume of refrigerant


Check for refrigerant gas leak


Replace cooler expansion valve


Check cooler compressor assembly


Replace heater radiator unit sub-assembly


Check No. 1 pressure switch


Proceed to "Air Conditioning Compressor Magnetic Clutch Circuit"


Proceed to "Compressor Lock Sensor Circuit"


Proceed to "Air Mix Damper Control Servo Motor Circuit (Driver Side)"


Proceed to "Air Mix Damper Control Servo Motor Circuit (Passenger Side)"


Proceed to "Air Inlet Damper Control Servo Motor Circuit"


Proceed to "Room Temperature Sensor Circuit"


Proceed to "Ambient Temperature Sensor Circuit"


Proceed to "Evaporator Temperature Sensor Circuit"


Proceed to "Driver Side Solar Sensor Short Circuit"


Proceed to "Front Passenger Side Solar Sensor Short Circuit"


Proceed to "BUS IC Communication Malfunction"


Proceed to "Air Conditioning Control Panel Circuit"


Replace air conditioning amplifier assembly


LIN communication system


Temperature Control: No temperature control (only MAX COOL or MAX WARM)

Proceed to "Air Conditioning Control Panel Circuit"


Proceed to "Air Mix Damper Control Servo Motor Circuit (Driver Side)"


Proceed to "Air Mix Damper Control Servo Motor Circuit (Passenger Side)"


Proceed to "Room Temperature Sensor Circuit"


Proceed to "Ambient Temperature Sensor Circuit"


Proceed to "Evaporator Temperature Sensor Circuit"


Proceed to "Driver Side Solar Sensor Short Circuit"


Proceed to "Front Passenger Side Solar Sensor Short Circuit"


Proceed to "BUS IC Communication Malfunction"


Replace air conditioning amplifier assembly


LIN communication system


No air inlet control

Proceed to "BUS IC Communication Malfunction"


Proceed to "Air Inlet Damper Control Servo Motor Circuit"


Replace air conditioning amplifier assembly


No air flow mode control

Proceed to "BUS IC Communication Malfunction"


Proceed to "Air Outlet Damper Control Servo Motor Circuit"


Replace air conditioning amplifier assembly


Engine coolant does not warm up quickly when engine is cold (PTC heater does not operate)*

Proceed to "PTC Heater Circuit"


Proceed to "Generator Signal Circuit"


Check generator assembly


Replace air conditioning amplifier assembly


Engine idle up does not occur or is continuous

Replace air conditioning amplifier assembly


Replace ECM


CAN communication system


Diagnostic trouble codes are not stored, and set mode is cleared when ignition switch is off

Proceed to "Back-up Power Source Circuit"


Replace air conditioning amplifier assembly


  • *: w/ PTC Heater
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