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INSPECTION PROCEDURE 8: Ambient temperature sensor system
 
 
 
 
TECHNICAL DESCRIPTION (COMMENT)
If the ambient temperature sensor system is defective, a malfunction may be present in the wiring harness between the ambient temperature sensor and the ETACS-ECU.
 
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the ambient temperature sensor
  • Malfunction of the ETACS-ECU
  • The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
 
 
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Inspection of the ambient temperature sensor.
Refer to .
Is the A/C pressure sensor normal?
Go to Step 2.
Replace the ambient temperature sensor (Refer to ).
 
STEP 2. Check of open circuit in AMB+ and AMB- line (ETACS-ECU) between ambient temperature sensor connector and ETACS-ECU connector.
Is the check result normal?
Go to Step 3.
Repair the connector(s) or wiring harness.
 
STEP 3. The heater controller assembly (A/C-ECU) using scan tool (M.U.T.-IIISE), check data list.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the electric motor switch to the OFF position before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect Scan Tool (M.U.T.-IIISE) ."
(2) All the following items in the data list should be normal (Refer to ).
Item No.19: Ambient temperature sensor
Is the check result normal?
Go to Step 4.
Replace the ETACS-ECU (Refer to GROUP 54A - ETACS-ECU ).
 
STEP 4. Retest the system.
Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).
Replace the ETACS-ECU (Refer to GROUP 54A - ETACS-ECU ).