DTC U0038 (PGM-FI System (1.5 L Engine))

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DTC U0038: PT-CAN Malfunction (TCM ECU BUS-OFF)

General Description

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

The controller area network (CAN) transmits/receives pulse signals to/from the control modules simultaneously by using two signal lines (H line and L line). When the transmission control module (TCM) cannot send the signals via the TM-CAN lines for set time, the powertrain control module (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
Elapsed time after the vehicle condition is turned to the ON mode	3 seconds	-
12 volt battery voltage [BATTERY]	10.0 V	-

[ ]: HDS Parameter

Malfunction Threshold

The PCM cannot send any signals via the TM-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.

TM-CAN circuit TM-CAN H line open
TM-CAN circuit TM-CAN L line open
TM-CAN circuit TM-CAN H line short to ground
TM-CAN circuit TM-CAN L line short to ground
TCM failure (include fuse blown)
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.