DTC B1000: Communication Bus Line Error

NOTE: If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN SYSTEM DIAGNOSIS TEST MODE A .

Clear the DTCs with the HDS.
Turn the ignition switch OFF, and then back ON (II).
Wait for 6 seconds or more.
Check for DTCs with the HDS.
Is DTC B1000 indicated?

YES -Go to step 5.

NO -Intermittent failure. The communication bus line is OK at this time. Check for loose or poor connections, or worn/shorted wires. If the connections are good, check the battery condition (see BATTERY ) and the charging system.
Check for DTCs with the HDS.
Are DTCs B1008, B1011, and B1032 also indicated with DTC B1000?

YES -Go to step 6.

NO -Faulty MICU; replace the under-dash fuse/relay box.
Turn the ignition switch OFF.

Disconnect the appropriate connector at each control unit in the table one at a time. Clear the DTCs, then recheck for DTCs after each unit is disconnected.

CONTROL UNIT SPECIFICATION

Control Unit	Appropriate Connector
MICU	Under-dash fuse/relay box connector Q (16P)
Gauge control module (tach)	36P connector
Immobilizer-keyless control unit	7P connector
Climate control unit	32P connector

Is DTC B1000 indicated with each individual unit disconnected?

YES -Go to step 8.

NO -Replace the control unit that was disconnected and B1000 did not reset.

Disconnect the under-dash fuse/relay box connector Q(16P).
Check for continuity between the under-dash fuse/ relay box connector Q(16P) No. 6 terminal and body ground.

Fig 1: Checking Continuity Between Under-Dash Fuse/ Relay Box Connector Q(16P) 6 Terminal And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Repair the short to ground in the wire.

NO -Go to step 10.
Turn the ignition switch ON (II).
Check for voltage between the under-dash fuse/ relay box connector Q (16P) No. 6 terminal and body ground.

Fig 2: Checking Voltage Between Under-Dash Fuse/ Relay Box Connector Q (16P) 6 Terminal And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there voltage?

YES -Repair the short to power in the wire between the under-dash fuse/relay box connector and the affected control unit.

NO -Faulty MICU; replace the under-dash fuse/relay box.