1A
A/C Signal Circuits Check (Vehicle with A/C)
Wiring Diagram
1. A/C compressor magnet clutch 6. “IG” fuse 11. Ignition switch
2. A/C switch 7. Evaporator temp. sensor 12. ECM
3. Blower fan motor 8. Relay box 13. 4WD controller
4. A/C condenser fan motor 9. A/C condenser fan relay 14. “IG2 SIG” fuse
5. Refrigerant pressure switch 10. A/C compressor relay *: RH steering vehicle
Troubleshooting
Step Action YES NO
1
Check evaporator temp. sensor
1) Disconnect ECM connectors with ignition switch at OFF position.
2) Check resistance between “E113-1” terminal and “E113-14” terminal.
Evaporator temp. sensor resistance
At 0 °C: 6.3 – 6.9 kΩ
At 25 °C: 1.8 – 2.2 kΩ
Is it within specification?
Go to Step 2.
Faulty A/C evaporator thermistor or its circuit.
2
Check A/C switch circuit
1) Check voltage at “E114-16” terminal under each condition given below.
A/C switch signal specification
With ignition switch ON and A/C switch OFF: 10 – 14 V
With ignition switch ON, A/C switch ON and heater fan switch 1st position or more: 0 – 1 V
Is check result satisfactory?
Go to Step 3.
“GRN/WHT” wire open or short, poor “E114-16” terminal connection. If wire and connection are OK, refer to A/C System Symptom Diagnosis .
3
Check A/C compressor signal
1) Check voltage at “E114-1” terminal under each condition given below.
A/C compressor signal specification
While engine running, A/C switch OFF: 10 – 14 V
While engine running, A/C switch ON: 0 V
Is check result satisfactory?
A/C compressor signal is in good condition, go to Step 4. If A/C compressor does not operate, refer to A/C System Symptom Diagnosis .
“PNK/BLU” or “PNK” wire open or short. Poor “E114-1” terminal connection. If wire and connection are OK, substitute a known-good ECM and recheck.
4
Check A/C condenser fan control signal
1) Check voltage at “E114-18” terminal under each condition given below.
A/C condenser fan control signal specification
While engine running, A/C switch OFF: 10 – 14 V
While engine running, A/C switch ON and heater fan switch 1st position or more: 0 V
Is check result satisfactory?
A/C signal circuits are in good condition. If A/C condenser fan does not operate, refer to A/C Condenser Fan Control System Check:M13A without VVT .
“PNK/BLK” wire open or short. Poor “E114-18” terminal connection. If wire and connection are OK, substitute a known-good ECM and recheck.
NOTE:
• When A/C evaporator thermistor temp. is below 3.5 °C (38.3 °F), A/C remain OFF (“E114-1” terminal voltage become 10 – 14 V). This condition is not abnormal.
• When engine coolant temp. is above 110 °C (230 °F), A/C condenser fan remain ON (“E114-18” terminal voltage become 0 – 1 V). This condition is not abnormal.