THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM(for Start Function): U0100; Lost Communication with ECM / PCM; 2016 - 2020 MY Sienna [12/2015

Last Modified: 04-05-2023	6.11:8.1.0	Doc ID: RM100000000VJJS
Model Year Start: 2016	Model: Sienna	Prod Date Range: [12/2015 - ]
Title: THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM(for Start Function): U0100; Lost Communication with ECM / PCM; 2016 - 2020 MY Sienna [12/2015 - ]

DTC

U0100

Lost Communication with ECM / PCM

DESCRIPTION

This DTC is stored when a malfunction in the CAN communication between the power management control ECU and ECM is detected.

HINT:

When the power management control ECU is replaced with a new one and the cable is connected to the negative (-) battery terminal, the power source mode changes to on (IG).
When the battery cable is disconnected and reconnected, the power source returns to the mode it was in before the battery cable was disconnected.

DTC Code	DTC Detection Condition	Trouble Area	DTC Output Confirmation Operation
U0100	CAN communication malfunction between the power management control ECU and ECM (1-trip detection logic*).	CAN communication system Power management control ECU	Wait 4 seconds or more after turning the engine switch on (IG).

Vehicle Condition when Malfunction Detected

Fail-safe Function when Malfunction Detected

No effect on vehicle behavior.

CAN communication is normal and the engine speed signal from the direct line is abnormal:

If the engine switch is pressed briefly, cranking stops when the starter OFF permission flag is received via CAN communication.
If the engine switch is pressed and held, cranking stops according to the engine speed signal sent via CAN communication.

CAN communication is abnormal and the engine speed signal from the direct line is normal:

If the engine switch is pressed briefly, cranking stops according to the engine speed signal from the direct line.
If the engine switch is pressed and held, cranking stops according to the engine speed signal from the direct line.

Both CAN communication and the engine speed signal from the direct line are abnormal:

If the engine switch is pressed briefly, cranking stops after 6 seconds elapse.
If the engine switch is pressed and held, cranking is maintained for a maximum of 30 seconds.

NOTICE:

When using the Techstream with the engine switch off, perform either of the following: 1) Turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the Techstream and vehicle begins, or 2) connect the Techstream to the vehicle, select the vehicle type under manual mode, and then enter the following menus: Body Electrical / Smart Key / Trouble Codes.
The smart key system uses multiplex communication. First perform the inspections in "How to Proceed with Troubleshooting" to confirm that there are no communication malfunctions before proceeding with troubleshooting (See page ).
Inspect the fuses of circuits related to this system before performing the following inspection procedure.
After performing repairs, perform the operation that fulfills the DTC output confirmation operation, and then confirm that no DTCs are output again.

DTC	Data List Item	Active Test Item
U0100	-	-

1.	CHECK FOR DTC

(a) Record any output DTCs (See page ).

NOTICE:

When using the Techstream with the engine switch off, perform either of the following: 1) Turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the Techstream and vehicle begins, or 2) connect the Techstream to the vehicle, select the vehicle type under manual mode, and then enter the following menus: Body Electrical / Smart Key / Trouble Codes.
The smart key system uses multiplex communication. First perform the inspections in "How to Proceed with Troubleshooting" to confirm that there are no communication malfunctions before proceeding with troubleshooting (See page ).

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

(See page )