Toyota Tacoma (2015-2018) Service Manual: Lost Communication with ECM / PCM (U0100,U0140,U0142,U0155,U1117)

Toyota Tacoma (2015-2018) Service Manual / 2gr-fks Starting / Smart Key System(for Start Function) / Lost Communication with ECM / PCM (U0100,U0140,U0142,U0155,U1117)

DESCRIPTION

These DTCs are stored when there is a CAN communication malfunction between the certification ECU (smart key ECU assembly), ECM, main body ECU (multiplex network body ECU) or combination meter assembly, and data from the option connector (bus buffer ECU) cannot be received.

HINT:

When the cable is disconnected and reconnected to the negative (-) battery terminal, the power source mode returns to the state it was in before the cable was disconnected.

DTC Code	DTC Detection Condition	Trouble Area	DTC Output Confirmation Operation
U0100	CAN communication error between the certification ECU (smart key ECU assembly) and ECM (1-trip detection*)	ECM	Turn the engine switch on (IG) and wait 10 seconds or more.
U0140 U0142	CAN communication error between the certification ECU (smart key ECU assembly) and main body ECU (1-trip detection*)	Main body ECU (multiplex network body ECU)	Always
U0155	CAN communication error between the certification ECU (smart key ECU assembly) and combination meter assembly (1-trip detection*)	Combination meter assembly	Turn the engine switch on (IG) and wait 10 seconds or more.
U1117	Data from the option connector (bus buffer ECU) cannot be received	Connector and branch wire of sub bus of option connector (bus buffer ECU) Internal malfunction of option connector (bus buffer ECU)	Turn the engine switch on (IG) and wait 10 seconds or more.

*: Only detected while a malfunction is present and the engine switch is on (IG)

Vehicle Condition and Fail-safe Function when Malfunction Detected

DTC Code	Vehicle Condition when Malfunction Detected	Fail-safe Function when Malfunction Detected
U0100	There is no effect on vehicle behavior.	If the following conditions are met, it is determined that the malfunction is not in the direct line (NE) but in CAN communication. When the engine switch is pressed, the system controls the engine based on the engine speed signal via direct line, causing the engine to stop cranking. When the engine switch is pressed and held, the system controls the engine based on the engine speed signal via direct line, causing the engine to stop cranking. If the following conditions are met, it is determined that there is a malfunction in both CAN communication and the direct line (NE). When the engine switch is pressed, the engine stops cranking after 6 seconds. When the engine switch is pressed and held, the engine remains cranking for up to 30 seconds.
U0140 U0142	Doors cannot be locked or unlocked. The warning (wireless buzzer) does not sound.	-
U0155	The warning (meter buzzer) does not sound and the meter does not indicate a warning.	-
U1117	The engine cannot be started using the wireless remote control function.	-

Related Data List and Active Test Items

DTC	Data List Item	Active Test Item
U0100 U0140 U0142 U0155 U1117	-	-

DTC

Data List Item

Active Test Item

U0100

U0140

U0142

U0155

U1117

CAUTION / NOTICE / HINT

NOTICE:

When using the Techstream with the engine switch off, connect the Techstream to the DLC3 and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the Techstream and the vehicle begins. Then select the vehicle type under manual mode and enter the following menus: Body Electrical / Smart Key. While using the Techstream, periodically turn a courtesy light switch on and off at intervals of 1.5 seconds or less to maintain communication between the Techstream and the vehicle.
After performing repairs, perform the operation that fulfills the DTC output confirmation operation, and then confirm that no DTCs are output again.

PROCEDURE

1.	CHECK FOR DTC

(a) Note any DTCs that are output (See page ).

GO TO CAN COMMUNICATION SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING)

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Diagnostic Trouble Code Chart
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