Refer to "57.HVAC Control 7A.Troubleshooting(Auto A/C) diagnostic system check-auto A/C controls".
1) Connect the scan tool.
2) Turn OFF the ignition switch.
3) Start the engine.
4) Observe the Evaporator Temperature Sensor A/D Input Raw Voltage parameter on the scan tool. Is the Evaporator Temperature Sensor A/D Input Raw Voltage parameter more than or equal to the specified value?
Value: 5.0 V
Yes
=>Go to Evaporator temperature sensor signal output voltage check.
No
Go to Intermittent conditions of auto A/C control system.
Refer to "208.HVAC 21D.Symptom intermittent conditions of auto A/C control system".
1) Turn OFF the ignition switch.
2) Disconnect the evaporator temperature sensor harness connector (B53).
3) Turn ON the ignition switch.
4) Measure the voltage between the evaporator temperature sensor signal circuit (pin 2 of B53) and the body ground with a DMM.
Refer to "LHD HVAC (Automatic Air Conditioner)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD HVAC (Automatic Air Conditioner)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Value: 4.5 to 5.5 V
The reading is more than the specified value.
=>Go to Inspection for short to power supply in evaporator temperature sensor signal circuit.
The reading is within the specified range.
=>Go to Evaporator temperature sensor signal voltage check using fused jumper wire.
The reading is less than the specified value.
=>Go to Inspection for open circuit in evaporator temperature sensor signal circuit.
1) Connect a fused jumper wire between the signal circuit and the low reference circuit of the evaporator temperature sensor (pins 1 and 2 of B53).
Refer to "LHD HVAC (Automatic Air Conditioner)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD HVAC (Automatic Air Conditioner)" in the ETM (wiring diagram). (Open using the ETM viewer.).
2) Observe the Evaporator Temperature Sensor A/D Input Raw Voltage parameter on the scan tool. Is the Evaporator Temperature Sensor A/D Input Raw Voltage parameter less than or equal to the specified value?
Value: 0.1 V
Yes
=>Go to Inspection for short to 5 V reference in evaporator temperature sensor signal circuit.
No
=>Go to Inspection for open circuit in evaporator temperature sensor low reference circuit.
1) Inspect the evaporator temperature sensor signal circuit between the auto A/C control unit harness connector (pin 7 of B10) and the evaporator temperature sensor (pin 2 of B53) for a short to the battery power supply circuit or a short to the ignition power supply circuit. Is the result normal?
Note
Refer to "LHD HVAC (Automatic Air Conditioner)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD HVAC (Automatic Air Conditioner)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
=>Go to Control panel replacement.
No
Repair the circuit as necessary.
1) Inspect the evaporator temperature sensor signal circuit between the auto A/C control unit harness connector (pin 7 of B10) and the evaporator temperature sensor (pin 2 of B53) for an open circuit or high resistance. Is the result normal?
Refer to "LHD HVAC (Automatic Air Conditioner)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD HVAC (Automatic Air Conditioner)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
=>Go to Auto A/C control unit harness connector inspection.
No
Repair the circuit as necessary.
1) Inspect the evaporator temperature sensor low reference circuit between the auto A/C control unit harness connector (pin 40 of B10) and the evaporator temperature sensor (pin 1 of B53) for an open circuit or high resistance. Is the result normal?
Caution
Refer to "LHD HVAC (Automatic Air Conditioner)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD HVAC (Automatic Air Conditioner)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
=>Go to Auto A/C control unit harness connector inspection.
No
Repair the circuit as necessary.
1) Inspect the evaporator temperature sensor signal circuit between the auto A/C control unit harness connector (pin 7 of B10) and the evaporator temperature sensor (pin 2 of B53) for a short to the 5 V reference circuit. Is the result normal?
Refer to "LHD HVAC (Automatic Air Conditioner)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD HVAC (Automatic Air Conditioner)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
=>Go to Evaporator temperature sensor harness connector inspection.
No
Repair the circuit as necessary.
1) Inspect for poor connections at the evaporator temperature sensor harness connector (pins 1 and 2 of B53). Is the connection status normal?
Refer to "LHD HVAC (Automatic Air Conditioner)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD HVAC (Automatic Air Conditioner)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
Replace the evaporator temperature sensor.
Refer to "7.HVAC 7B.Heater Ventilator Airconditioner evaporator core removal".
Refer to "7.HVAC 7B.Heater Ventilator Airconditioner evaporator core installation".
No
Repair the connections as necessary.
1) Inspect for poor connections at the auto A/C control unit harness connector (pins 7 and 40 of B10). Is the connection status normal?
Refer to "LHD HVAC (Automatic Air Conditioner)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD HVAC (Automatic Air Conditioner)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
=>Go to Control panel replacement.
No
Repair the connections as necessary.
Note
Refer to "7.HVAC 7B.Heater Ventilator Airconditioner control panel and control lever removal".
Refer to "7.HVAC 7B.Heater Ventilator Airconditioner control panel and control lever installation".
Refer to "7.HVAC 7B.Heater Ventilator Airconditioner control panel and control lever setting".
Procedure completion
1) Clear the DTC with a scan tool.
2) Turn OFF the ignition switch.
3) Start the engine.
4) Observe the DTC information with a scan tool.