DTC U12AA

DTC U12AA: EPP-CAN Malfunction (Powertrain Control Module (PCM)-SBW Shifter)

General Description

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

The electric power plant-controller area network (EPP-CAN) transmits/receives pulsing signals to/from the control modules simultaneously by using two signal lines (H line and L line). When the powertrain control module (PCM) does not receive the signals from the shift by wire (SBW) shifter control module via the EPP-CAN lines for a set time, the PCM detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type

Execution	Continuous
Sequence	None
Duration	1 second or more
DTC Type	One drive cycle, MIL on

Enable Conditions

Condition	Minimum	Maximum
12 volt battery voltage [Battery]	10.0 V	-
Elapsed time after the vehicle condition is turned to the ON mode	3 seconds	-

[ ]: HDS Parameter

Malfunction Threshold

The PCM does not receive any signals via the EPP-CAN lines for at least 1 second.

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.

EPP-CAN circuit EPP-CAN A_H line open
EPP-CAN circuit EPP-CAN A_L line open
EPP-CAN circuit EPP-CAN A_H line short to ground
EPP-CAN circuit EPP-CAN A_L line short to ground
SBW shifter control module failure (include fuse fall-outs)
PCM internal circuit failure

Diagnosis Details

Conditions for setting the DTC

When a malfunction is detected, the MIL comes on and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the PCM memory.

Conditions for clearing the DTC

The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the 12 volt battery.