B1000

DTC B1000: Control Panel Communication Error














DTC SET CONDITION

DTC B1000 will be set when the communication between A/C-ECU and A/C control panel cannot be performed.

TECHNICAL DESCRIPTION (COMMENT)

Current trouble

- The A/C-ECU, the A/C control panel, or connector(s) or wiring between the two may be defective.

Past trouble

- If DTC B1000 is stored as a past trouble, carry out diagnosis with particular emphasis on wiring and connector(s) between the A/C-ECU and the A/C 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 A/C control panel.
- Malfunction of the A/C-ECU.

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.

Use scan tool MB991958 to diagnose the CAN bus lines.

(1)Connect scan tool MB991958. Refer to "How to connect the Scan Tool (M.U.T.-III) Reading and Clearing Diagnostic Trouble Codes.

(2)Turn the ignition switch to "ON" position.

(3)Diagnose the CAN bus line.

Q. Is the check result satisfactory?

YES Go to Step 2.
NO Repair the CAN bus lines. Repair the CAN bus lines CAN Bus Diagnostics Chart).
STEP 2. Check A/C-ECU connector C-210 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Is A/C-ECU connector C-210 in good condition?

YES Go to Step 3.
NO Repair or replace the connector. Harness Connector Inspection.
STEP 3. Check the wiring harness between A/C-ECU connector C-210 (terminal 9) and A/C control panel connector C-216 (terminal 9).

- Check the A/C control panel signal line for open and short circuit.

Q. Is the wiring harness between A/C-ECU connector C-210 (terminal 9) and A/C control panel connector C-216 (terminal 9) in good condition?

YES Go to Step 4.
NO Repair the wiring harness.
STEP 4. 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 A/C control panel. Then go to Step 5.
NO It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions.
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 A/C-ECU.
NO It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions.