Toyota Tundra Service Manual: Lost Communication with ECM / PCM "A" (U0100,U0104,U0122,U0125,U0126,U0129,U0137)

Toyota Tundra Service Manual / Engine, Hybrid System / Cruise Control / Dynamic Radar Cruise Control System / Lost Communication with ECM / PCM "A" (U0100,U0104,U0122,U0125,U0126,U0129,U0137)

DESCRIPTION

The millimeter wave radar sensor assembly and ECM communicate with each sensor and ECU via CAN communication.

If any malfunction is detected in a CAN communication circuit, one or more CAN communication system DTCs are stored.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

U0100

Lost Communication with ECM / PCM "A"

 Condition 1:
  • While the vehicle speed is 36 km/h (22 mph) or more and the dynamic radar cruise control system is operating, a communication error between the ECM and the millimeter wave radar sensor assembly is detected for approximately 1 second or more.
Condition 2:
  • While the vehicle speed is 36 km/h (22 mph) or more and the dynamic radar cruise control system is operating, the ECM continuously receives a communication cut-off signal from the skid control ECU (brake actuator assembly) for approximately 1 second or more.
Condition 1:
  • CAN communication system
  • ECM
  • Millimeter wave radar sensor assembly
Condition 2:
  • CAN communication system
  • ECM
  • Skid control ECU (brake actuator assembly)

U0104

Lost Communication with Cruise Control Module

While the vehicle speed is 36 km/h (22 mph) or more and the dynamic radar cruise control system is operating, a communication error between the ECM and the millimeter wave radar sensor assembly is detected for approximately 1 second or more.
  • CAN communication system
  • ECM
  • Millimeter wave radar sensor assembly

U0122

Lost Communication with Vehicle Dynamics Control Module

When the ignition switch is ON and the dynamic radar cruise control system is operating, a communication error between the skid control ECU (brake actuator assembly) and the ECM is detected for approximately 2.6 seconds or more.
  • CAN communication system
  • ECM
  • Skid control ECU (brake actuator assembly)

U0125

Lost Communication with Yaw Rate Sensor Module

While the vehicle speed is 36 km/h (22 mph) or more and the dynamic radar cruise control system is operating, a communication error between the yaw rate sensor and the millimeter wave radar sensor assembly is detected for approximately 1 second or more.
  • CAN communication system
  • Yaw rate sensor (airbag sensor assembly)
  • Millimeter wave radar sensor assembly

U0126

Lost Communication with Steering Angle Sensor Module

While the vehicle speed is 36 km/h (22 mph) or more and the dynamic radar cruise control system is operating, a communication error between the steering sensor and the millimeter wave radar sensor assembly is detected for approximately 1 second or more.
  • CAN communication system
  • Steering sensor
  • Millimeter wave radar sensor assembly

U0129

Lost Communication with Brake System Control Module

While the vehicle speed is 36 km/h (22 mph) or more and the dynamic radar cruise control system is operating, a communication error between the skid control ECU (brake actuator assembly) and the millimeter wave radar sensor assembly is detected for approximately 2.5 seconds or more.
  • CAN communication system
  • Skid control ECU (brake actuator assembly)
  • Millimeter wave radar sensor assembly

U0137

Lost Communication with Trailer Brake Control Module

While the vehicle speed is 36 km/h (22 mph) or more and the dynamic radar cruise control system is operating, a communication error between the trailer brake control ECU (brake control with bracket relay) and the ECM is detected for approximately 2.1 seconds or more.
  • CAN communication system
  • Trailer brake control ECU (brake control with bracket relay)
  • ECM

PROCEDURE

1.

CHECK FOR DTCs (RADAR CRUISE 1 AND RADAR CRUISE 2)

(a) Clear the DTCs.

Click here

(b) Make sure that the DTC detection conditions are met.

HINT:

If the detection conditions are not met, the system cannot detect the malfunction.

  1. Turn the ignition switch to ON.
  2. Turn the dynamic radar cruise control system on using the cruise control main switch (ON-OFF button).
  3. Drive the vehicle at 36 km/h (22 mph) or more for 5 seconds or more.

(c) Check for DTCs.

Click here

Result

Proceed to

DTC U0100, U0104, U0122, U0125, U0126, U0129 and U0137 are not output

A

DTC U0100, U0104, U0122, U0125, U0126, U0129 or U0137 is output

B
A

USE SIMULATION METHOD TO CHECK

B

GO TO CAN COMMUNICATION SYSTEM

    Terminals Of Ecu

    Vehicle Control History

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