Toyota Tundra Service Manual: Lost Communication with ECM / PCM "A" (U0100,U0122)

Toyota Tundra Service Manual / Engine, Hybrid System / Wf1am Transfer / Touch Select 2-4 And High-low System / Lost Communication with ECM / PCM "A" (U0100,U0122)

DESCRIPTION

This DTC is detected if communication is lost between the ECM and skid control ECU.

DTC Code

DTC Detection Condition

Diagnosis Condition
Malfunction Status
Malfunction Time
Other

Trouble Area

U0100

Ignition switch ON
Communication is lost between ECM and 4 wheel drive control ECU
5 seconds or more
1 trip detection logic

CAN communication system

U0122

Ignition switch ON
Communication is lost between skid control ECU and 4 wheel drive control ECU
0.7 seconds or more
1 trip detection logic

CAN communication system

CAUTION / NOTICE / HINT

NOTICE:

When the data in the ECM or skid control ECU is being overwritten, the indicator light may rapidly blink 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 is overwritten.

PROCEDURE

1.	RECONFIRM DTC

(a) Clear the DTCs (See page ).

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

Result

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

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

USE SIMULATION METHOD TO CHECK

Terminals Of Ecu

Invalid Data Received from Vehicle Dynamics Control Module (U0416)

See More:

Toyota Tundra Owners Manual > Steps to take in an emergency: If you think something is wrong
If you notice any of the following symptoms, your vehicle probably needs adjustment or repair. Contact your Toyota dealer as soon as possible. Visible symptoms Fluid leaks under the vehicle. (Water dripping from the air conditioning after use is normal.) Flat-looking tires or uneven tire wear Engin ...