Toyota Tacoma (2015-2018) Service Manual: Lost Communication with ECM / PCM "A" (U0100,U0122)

Toyota Tacoma (2015-2018) Service Manual / Vf2cm Transfer / Touch Select 2-4 And High-low System / Lost Communication with ECM / PCM "A" (U0100,U0122)

DESCRIPTION

This DTC is output when communication is lost with the skid control ECU (brake actuator assembly) or ECM.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area
U0100	Lost Communication with ECM / PCM "A"	Diagnosis Condition: Ignition switch turned to ON (3 seconds elapse after ignition switch is turned to ON) Malfunction Status: Communication is lost between ECM and 4 wheel drive control ECU Malfunction Time: 1.85 seconds or more Other: 1 trip detection logic	CAN communication system
U0122	Lost Communication with Vehicle Dynamics Control Module	Diagnosis Condition: Ignition switch turned to ON (3 seconds elapse after ignition switch is turned to ON) Malfunction Status: Communication is lost between skid control ECU and 4 wheel drive control ECU Malfunction Time: 0.72 seconds or more Other: 1 trip detection logic	CAN communication system

CAUTION / NOTICE / HINT

NOTICE:

When the data in the ECM and skid control ECU (brake actuator assembly) is being overwritten, a message is displayed on the multi-information display and the indicator light rapidly blinks due to the 4 wheel drive control ECU detecting a communication malfunction (blinks at 0.25 second intervals (0.25 seconds on and 0.25 seconds off)), but this is not a malfunction.
Clear all DTCs, since DTCs are stored after the data in the ECM or skid control ECU (brake actuator assembly) is overwritten.

PROCEDURE

1.	PERFORM DTC

(a) Clear the DTCs (See page (b) Check if the same DTCs are output (See page ).

(b) Check if the same DTCs are output (See page Result ).

Result

Result	Proceed to
DTC is output	A
DTC is not output	B

CHECK CAN COMMUNICATION SYSTEM

USE SIMULATION METHOD TO CHECK

Clutch Switch Circuit

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4WD Control Switch Circuit

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Other materials:

Inspection
INSPECTION PROCEDURE 1. INSPECT BRAKE BOOSTER PUMP ASSEMBLY (a) Connect the positive (+) lead from the battery to the red cable of the pump, and the negative (-) lead to the black cable. (b) Check the brake booster pump operation. OK: Operation sound is heard. ...

On-vehicle Inspection
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Steering Pad Switch Circuit
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