DTC Advanced Diagnostics: U0038 (K20C2 (CVT System))

DTC Advanced Diagnostics: U0038

DTC U0038:TM-CAN Malfunction (TCM-PCM)

General Description

The transmission control module (TCM) and the powertrain control module (PCM) uses communication line (TM-CAN_H and TM-CAN_L) to transmit/receive multiple signals simultaneously. When the information is not sent from the PCM via the TM-CAN lines and this condition continues for a specified time, the TCM detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type

Execution	Continuous
Sequence	None
Duration	1.5 seconds or more
DTC Type	One drive cycle, MIL on, Shift position indicator blinks

Enable Conditions

Condition	Minimum	Maximum
12 volt battery voltage [Battery Voltage]	10.0 V	–

[ ]: HDS Parameter

Malfunction Threshold

The TCM does not receive any signals via the TM-CAN lines for at least 1.5 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.

	PCM failure (include fuse fall-outs)
	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 internal circuit failure

Diagnosis Details

Conditions for setting the DTC

When a malfunction is detected, the MIL comes on, the shift position indicator blinks, and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the TCM memory.

Conditions for clearing the DTC

The shift position indicator comes off by turning the vehicle to the OFF (LOCK) mode. 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.