1) Connect the scan tool.
2) Check whether the scan tool powers up. Does the scan tool power up?
Yes
=>Go to Auto A/C control unit communication verification.
No
Go to Scan tool does not power up.
Refer to "51.Engine Control 1A.Troubleshooting(4JJ3 with DPD) Scan tool does not power up".
Refer to "51.Engine Control 1A.Troubleshooting(4JJ3 without DPD) Scan tool does not power up".
Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) Scan tool does not power up".
1) Verify that communication can be established with the auto A/C control unit using the scan tool. Can communication with the auto A/C control unit be established?
Yes
The system is normal.
No
1) Inspect for poor connections at the DLC (pins 6 and 14 of C19). Is the connection status normal?
Refer to "LHD Controller Area Network (Except Central Gateway C/U)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD Controller Area Network (Except Central Gateway C/U)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
=>Go to Auto A/C control unit harness connector inspection.
No
Repair the connections as necessary.
1) Inspect for poor connections at the auto A/C control unit harness connector (pins 18 and 19 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
No
Repair the connections as necessary.
1) Inspect the following fuses. Is the result normal?
Yes
=>Go to Inspection for open circuit in battery power supply circuit.
No
Replace the fuse as necessary. If the fuse blows out again, repair the short to ground in the circuits relating to the fuse.
1) Turn OFF the ignition switch.
2) Disconnect the auto A/C control unit harness connector (B10).
3) Connect a test lamp between the battery power supply circuit of the auto A/C control unit harness connector (pin 1 of B10) and the body ground. Does the test lamp illuminate?
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 Inspection for open circuit in ignition power supply circuit.
No
Repair the open circuit or high resistance in the battery power supply circuit between the METER (+B) 10A fuse and the auto A/C control unit (pin 1 of B10).
1) Turn ON the ignition switch.
2) Connect a test lamp between the ignition power supply circuit of the auto A/C control unit harness connector (pin 21 of B10) and the body ground. Does the test lamp illuminate?
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
No
Repair the open circuit or high resistance in the battery power supply circuit between the ELEC (IG1) 10A fuse and the auto A/C control unit (pin 21 of B10).
1) Connect a test lamp between the battery power supply circuit of the auto A/C control unit harness connector and the ground circuit (pins 1, 20, 38, and 40 of B10). Does the test lamp illuminate?
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 Inspection for open circuit and short circuit in CAN communication circuit.
No
=>Go to Inspection for open circuit in ground circuit.
1) Inspect the ground circuit between the auto A/C control unit (pins 1, 20, 38, and 40 of B10) and the body ground 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
Repair corrosion and tightening of the auto A/C control unit ground terminals.
No
Repair the circuit as necessary.
1) Inspect the CAN Low circuit and CAN High circuit between the auto A/C control unit (pins 18 and 19 of B10) and the DLC (pins 6 and 14 of C19) for the following. Is the result normal?
Refer to "LHD Controller Area Network (Except Central Gateway C/U)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD Controller Area Network (Except Central Gateway C/U)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
=>Go to Control panel replacement.
No
Repair the circuit 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) Connect all of the removed fuses and harness connectors.
2) Turn OFF the ignition switch.
3) Turn ON the ignition switch.
4) Verify that communication can be established with the auto A/C control unit using the scan tool. Can communication with the auto A/C control unit be established?
Yes
The system is normal.
No