[Previous][Next]
DTC B1125: Air outlet damper circuit open
DTC B1128: Air outlet damper circuit short
 
 
 
 
DTC SET CONDITION
  • When the air conditioning outlets cannot be switched, open circuit (DTC B1125) and short circuit (DTC B1128) of the mode selection damper control motor circuit are set.
 
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the mode selection damper control motor
  • Malfunction of the motor lever
  • Malfunction of the upper case assembly (integrated mode selection damper)
  • The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
  • Malfunction of the A/C controller assembly (A/C-ECU)
 
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Using scan tool (M.U.T.-IIISE), check actuator test.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect the Scan Tool (M.U.T.-IIISE) ."
(2) Carry out the actuator test (Refer to ).
Item No.8: Mode selection damper
Is the check result normal?
Go to Step 3.
Go to Step 2.
 
STEP 2. Check of open circuit in IG1, MA, MA', MB and MB' line between mode selection damper control motor connector and A/C controller assembly (A/C-ECU) connector.
Is the check result normal?
Go to Step 3.
Repair the connector(s) or wiring harness.
 
STEP 3. Check the operation of the mode selection damper.
(1) Remove the mode selection damper control motor.
(2) Check if there is any foreign material around the mode lever of the A/C unit, and remove it if necessary.
(3) Operate the blower and turn the mode lever of the A/C unit by hand to check whether the mode selection damper works normally.
OK: The air is distributed through the appropriate air outlet (When the mode lever is turned fully toward the vehicle front direction, the air is distributed through the DEF only. When the mode lever is turned fully toward the vehicle rear direction, the air is distributed through the FACE only).
Is the check result normal?
Go to Step 4.
Replace the upper case assembly or motor lever.
 
STEP 4. Check whether the DTC is set again.
Is the DTC set?
Replace the mode selection damper control motor. Then go to Step 5.
The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).
 
STEP 5. Check whether the DTC is set again.
Is the DTC set?
Replace the A/C controller assembly (A/C-ECU).
This procedure is complete.