Toyota Tacoma manuals

Toyota Tacoma 2015-2018 Service Manual: Lost Communication with ECM / PCM "A" (U0100,U0125,U0126,U0129)

Toyota Tacoma 2015-2018 Service Manual / Cruise Control / Dynamic Radar Cruise Control System(for 2gr-fks) / Lost Communication with ECM / PCM "A" (U0100,U0125,U0126,U0129)

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

MIL

U0100

Lost Communication with ECM / PCM "A"

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

Does not come on

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

Does not come on

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 angle sensor and the millimeter wave radar sensor assembly is detected for approximately 1 second or more.

  • CAN communication system
  • Steering angle sensor
  • Millimeter wave radar sensor assembly

Does not come on

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 (master cylinder solenoid)*1 or skid control ECU (brake actuator assembly)*2 and the millimeter wave radar sensor assembly is detected for approximately 2.5 seconds or more.

  • CAN communication system
  • Skid control ECU (master cylinder solenoid)*1
  • Skid control ECU (brake actuator assembly)*2
  • Millimeter wave radar sensor assembly

Does not come on

  • *1: for Hydraulic Brake Booster
  • *2: for Vacuum Brake Booster

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.

(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, U0125, U0126 and U0129 are not output

A

DTC U0100, U0125, U0126 or U0129 is output

B

A

USE SIMULATION METHOD TO CHECK

B

GO TO CAN COMMUNICATION SYSTEM

Communication Error from ECM to VSC Invalid Serial Data Received (P163181)
DESCRIPTION The ECM sends signals such as dynamic radar cruise control operation signals, brake operation demand signals and buzzer operation demand signals to the skid control ECU (master cylind ...

Lost Communication With ECM/PCM "A" Missing Message (U010087,U010487,U012287)
DESCRIPTION The ECM communicates 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 ...

Other materials:

Problem Symptoms Table
PROBLEM SYMPTOMS TABLE HINT: Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each sy ...

Lost Communication With Vehicle Dynamics Control Module (U0122)
DESCRIPTION This DTC is detected if communication is lost with the skid control ECU (brake actuator assembly). DTC No. Detection Item DTC Detection Condition Trouble Area U0122 Lost Communication with Vehicle Dynamics Contro ...

Fail-safe Chart
FAIL-SAFE CHART HINT: If any of the following auto cancel conditions are detected while the dynamic radar cruise control system is controlling vehicle speed, the system clears the stored vehicle speed and cancels control of vehicle speed by the dynamic radar cruise control system. Automatic ...

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