Inspection Procedure 3: The ambient air temperature is not displayed normally. <Vehicles with auto A/C>


CIRCUIT OPERATION



  • For the vehicles with auto A/C, the RV meter receives and displays the ambient temperature information from the A/C-ECU by CAN communication. Also, the ambient temperature displayed on the RV meter is corrected by the vehicle speed of the vehicle speed sensor.
  • If the function type is set as 3 or 4 by mistake, the ambient temperature cannot be displayed.

COMMENTS ON TROUBLE SYMPTOM



PROBABLE CAUSES



  • Malfunction of the A/C-ECU
  • Malfunction of the CAN bus line
  • Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. Check the function type in the service mode.
Check that the function type is set as 1 or 2 in the service mode. (Refer to .)

Q. Is the check result satisfactory?
Go to Step 2
Set the function type again in the service mode, and recheck the trouble symptom. (Refer to .)

STEP 2. Check the RV meter.
Check that the average vehicle speed and the average fuel consumption are displayed normally, and check that the connection with the vehicle speed sensor is normal.

Q. Is the check result satisfactory?
Go to Step 3
Perform the troubleshooting, Inspection Procedure 2: "The drive information is not displayed normally". (Refer to .)

STEP 3. M.U.T.-III CAN bus diagnostics
Use the M.U.T-III to diagnose the CAN bus lines.

Q. Is the check result satisfactory?
Go to Step 4
Repair the CAN bus lines (Refer to GROUP 54C, Diagnosis - Can Bus Diagnostics Table ). After diagnosing the CAN bus lines, go to Step 4.

STEP 4. M.U.T-III other system diagnosis code.
Check whether the A/C-ECU diagnosis code is set.

Q. Is the diagnosis code set?
Diagnose A/C-ECU (Refer to GROUP 55B, Troubleshooting ), and then go to Step 5.
Go to Step 5

STEP 5. Recheck for malfunction.

Q. Is a malfunction eliminated?
If no malfunctions are found in all steps, an intermittent malfunction is suspected. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction .
Replace the RV meter.