Code No. B1000: Communication error with control panel










COMMENTS ON TROUBLE SYMPTOM
This code will be set when the A/C-ECU cannot receive information from the A/C control panel.

PROBABLE CAUSES

  • Malfunction of the A/C control panel
  • Damaged the wiring harness or connectors
  • Malfunction of the A/C-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-120 A/C control panel connector and C-111 A/C-ECU connector

Q. Is the check result normal?
Go to Step 2.
Repair the connector.

STEP 2. Check the wiring harness between C-120 A/C control panel connector (terminals 9 and 1) and C-111 A/C-ECU connector (terminals 9 and 10).

  • Check the AC control panel signal line and earth line for open or short circuit.

Q. Is the check result normal?
Go to Step 3.
Repair the wiring harness.

STEP 3. Check whether the diagnosis code is reset.
Replace the A/C control panel, and erase the diagnosis code. Then check that no diagnosis code is being set.

Q. Is the diagnosis code set?
Replace the A/C-ECU.
The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).