DTC U1220: DC-DC Converter Lost Communication With Battery Condition Monitor Module (34) (2017)

General Description

Courtesy of HONDA, U.S.A., INC.

The DC-DC converter uses an internal timer to measure the intervals between serial communication data updates. When an update is not received for a specified time, the battery condition monitor module detects a controller area network (CAN) communication reception malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type, OBD Status

Execution	Continuous
Sequence	None
Duration	2 seconds or more
DTC Type	Two drive cycles, MIL off, POWER SYSTEM indicator on
OBD Status	PASSED/FAILED/NOT COMPLETED (STILL TESTING)

Enable Conditions

Condition	Minimum	Maximum
Battery condition monitor module power-supply voltage	10.2 V	-
Vehicle	ON mode

Malfunction Threshold

The serial communication data is not updated for at least 2 seconds.

Possible Cause

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.

DC-DC converter F-CAN line open
DC-DC converter F-CAN line short to ground
DC-DC converter internal circuit failure
Battery condition monitor module internal circuit failure

Confirmation Procedure

Operating condition

Turn the vehicle to the ON mode, and wait for at least 10 seconds.

With the HDS

None.

Diagnosis Details

Conditions for setting the DTC

When a malfunction is detected during the first drive cycle, a Pending DTC is stored is the battery condition monitor module memory. If the malfunction returns in the next (second) drive cycle, the POWER SYSTEM indicator comes on and a Confirmed DTC and the freeze data are stored.

Conditions for clearing the DTC

The POWER SYSTEM indicator is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The POWER SYSTEM indicator, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by the battery condition monitor module reset.