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

DESCRIPTION While depressing the clutch pedal, the clutch start switch assembly sends a signal to terminal MTN of the 4 wheel drive control ECU. While the signal is input, switching between H4 an ...

4WD Control Switch Circuit

WIRING DIAGRAM PROCEDURE 1. CONFIRM PROBLEM SYMPTOM (a) Confirm the problem symptoms. Result Result Proceed to The 4WD ind ...

Other materials:

Cruise Control Input Circuit (P0575)
DESCRIPTION This DTC is stored when there is a malfunction in the ECM. DTC No. Detection Item DTC Detection Condition Trouble Area P0575 Cruise Control Input Circuit Either of the following conditions is met: ...

Vehicle Speed Sensor Circuit (C1AA3)
DESCRIPTION The forward recognition camera receives vehicle speed signals from the skid control ECU. If the skid control ECU receives a vehicle speed sensor malfunction signal, it informs the forward recognition camera via CAN communication, and DTC C1AA3 is stored. DTC No. ...

Precaution
PRECAUTION 1. PRECAUTION NOTICE: When disconnecting the cable from the negative (-) battery terminal, initialize the following systems after the cable is reconnected (See page ). Perform the Reset Memory procedures (A/T initialization) after replacing the automatic transmi ...