DTC U1220 (Battery Condition Monitor Module)
DTC U1220: DC-DC Converter Serial Communication Transmit Error
General Description
The DC-DC converter uses an internal timer to measure the intervals between CAN communication data updates. When an update is not received for a specified time, the battery condition monitor module detects a CAN communication reception malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 2 seconds or more |
| DTC Type | Two drive cycles, MIL off, POWER SYSTEM indicator on, 12 VOLT CHARGING SYSTEM indicator off |
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| Battery condition monitor module power-supply voltage | 10.2 V | - |
| Vehicle | ON mode | |
Malfunction Threshold
The CAN 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.
- F-CAN circuit F-CAN A_H line open
- F-CAN circuit F-CAN A_L line open
- F-CAN circuit F-CAN A_H line short
- F-CAN circuit F-CAN A_L line short
- Power control unit (PCU) 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 in the battery condition monitor module memory. If the malfunction returns in the next (second) drive cycle, a Confirmed DTC and the freeze data are stored. The MIL does not come on.
Conditions for clearing the DTC
The Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool clear command or the battery condition monitor module reset.