Control Panel Improperly Assembled [Vehicles Without A/C]

DTC B223B: Control Panel Improperly Assembled [Vehicles Without A/C]

A/C Control Panel Circuit:

DTC SET CONDITION
DTC B223B will be set when the heater control panel sends an abnormal data, the heater control panel for RHD is improperly assembled, or the ETACS-ECU sends incorrect vehicle information (information for RHD is sent).

TECHNICAL DESCRIPTION (COMMENT)

Current trouble
- The heater control module, the heater control panel, or connector(s) or wiring between the two may be defective.

Past trouble
- If DTC B223B is stored as a past trouble, carry out diagnosis with particular emphasis on wiring and connector(s) between the heater control module and the heater control panel. If the connectors and wiring are normal, and obviously the ECU is the cause of the trouble, replace the ECU. If in doubt, do not replace the ECU.

TROUBLESHOOTING HINT
- Malfunction of connector.
- Malfunction of the harness.
- Malfunction of the heater control panel.
- Malfunction of the heater control module.

DIAGNOSIS

Required Special Tool:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, diagnose the CAN bus line

CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.







1. Connect scan tool MB991958. Refer to "How to connect the Scan Tool (M.U.T.-III)." How to Connect the Scan Tool (M.U.T.-III)
2. Turn the ignition switch to the "ON" position.
3. Diagnose the CAN bus line.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the CAN bus line found to be normal?

YES : Go to Step 2.

NO : Repair the CAN bus line.

STEP 2. Recheck for diagnostic trouble code.

Recheck if the DTC is set
1. Erase the DTC.
2. Turn the ignition switch to "ON" position
3. Check if the DTC is set.

Q: Is the DTC set?

YES : Go to Step 3.

NO : It can be assumed that this malfunction is intermittent.

STEP 3. Check heater control panel connector C-138 and heater control module connector C-53 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are heater control panel connector C-138 and heater control module connector C-53 in good condition?

YES : Go to Step 4.

NO : Repair or replace the connector.

STEP 4. Check the wiring harness between heater control module connector C-53 (terminal 9) and heater control panel connector C-138 (terminal 9).

- Check the heater control panel signal line and ground line for open and short circuit.

Q: Is the wiring harness between heater control module connector C-53 (terminal 9) and heater control panel connector C-138 (terminal 9) in good condition?

YES : Go to Step 5.

NO : Repair the wiring harness.

STEP 5. Recheck for diagnostic trouble code.

Recheck if the DTC is set
1. Erase the DTC.
2. Turn the ignition switch to "ON" position
3. Check if the DTC is set.

Q: Is the DTC set?

YES : Replace the heater control panel. Then go to Step 6.

NO : It can be assumed that this malfunction is intermittent.

STEP 6. Recheck for diagnostic trouble code.

Recheck if the DTC is set
1. Erase the DTC.
2. Turn the ignition switch to "ON" position
3. Check if the DTC is set.

Q: Is the DTC set?

YES : Replace the heater control module.

NO : It can be assumed that this malfunction is intermittent.