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DTC B112A: PA. A/M damper circuit open <Vehicles with dual-zone auto A/C>
DTC B112B: PA. A/M damper circuit short <Vehicles with dual-zone auto A/C>
 
 
 
 
DTC SET CONDITION
  • When the air conditioning outlet temperature on the passenger's seat side cannot be adjusted, open circuit (DTC B112A) and short circuit (DTC B112B) of the air mixing damper control motor circuit are set.
 
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the air mix damper control motor (Passenger’s side)
  • 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. Check the compressor operation.
Check that the compressor operates under the following conditions.
  • Engine operation
  • Air volume control dial: Maximum
  • Air conditioning switch: ON
  • Temperature control dial: MAX COOL
Is the check result normal?
Go to Step 2.
Refer to inspection procedure 5 "The A/C compressor does not work" .
 
STEP 2. 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.6: Passenger’s side air mixing damper
Is the check result normal?
Go to Step 4.
Go to Step 3.
 
STEP 3. Check of open circuit in IG1, PA, PA’, PB and PB’ line between air mixing damper control motor connector and A/C controller assembly (A/C-ECU) connector.
Is the check result normal?
Go to Step 4.
Repair the connector(s) or wiring harness.
 
STEP 4. Check whether the DTC is set again.
Is the DTC set?
Replace the air mix damper control motor (Passenger’s side). 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.