Climate Control System DTC I-A4

DTC screen I-A4  : Climate control unit lost communication with center display unit

NOTE:  The DTC may be stored due to the grounding failure or the power source failure at the center display (the grounding inspection and the power source inspection on each control unit are required prior to this checking process).

1. Problem verification

   -1. Turn the vehicle to the OFF (LOCK) mode and then the ON mode.

   -2. Do the Self-Diagnostic Function with the climate control unit .

   -3. Check for DTCs.

   Is Error on the DTC screen I-A4 indicated?

   YES 

   The failure is duplicated. Go to step 2.

   NO 

   Intermittent failure, the system is OK at this time. Check for loose wires or poor connections.

2. Open wire check (B-CAN_H line)

   -1. Turn the vehicle to the OFF (LOCK) mode.

   -2. Disconnect the following connectors.

   Audio unit connector A (24P) (without navigation)

   Audio-navigation unit connector A (24P) (with navigation)

   Climate control unit connector A (32P)

   -3. Measure the resistance between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	Audio unit connector A (24P) (without navigation): disconnected
   	Audio-navigation unit connector A (24P) (with navigation): disconnected
   	Climate control unit connector A (32P): disconnected

   Test point 1	Audio unit connector A (24P) No. 14 (without navigation)
   	Audio-navigation unit connector A (24P) No. 14 (with navigation)
   Test point 2	Climate control unit connector A (32P) No. 25

   Is there 1.0 Ω or less?

   YES 

   The B-CAN_H wire is OK. Go to step 3.

   NO 

   Repair an open in the B-CAN_H wire.

3. Open wire check (B-CAN_L line)

   -1. Measure the resistance between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	Audio unit connector A (24P) (without navigation): disconnected
   	Audio-navigation unit connector A (24P) (with navigation): disconnected
   	Climate control unit connector A (32P): disconnected
   Test point 1	Audio unit connector A (24P) No. 24 (without navigation)
   	Audio-navigation unit connector A (24P) No. 24 (with navigation)
   Test point 2	Climate control unit connector A (32P) No. 8

   Is there 1.0 Ω or less?

   YES: Without navigation

   Replace the audio unit .

   YES: With navigation

   Replace the audio-navigation unit .

   NO 

   Repair an open in the B-CAN_L wire.