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Home >> Toyota >> 2017 >> 4Runner TRD Pro >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Anti-Theft Systems >> Smart Key System (For Start Function) - Diagnostic Codes & Symptom Tests >> SMART KEY SYSTEM (for Start Function) >> DTC U0100: Lost Communication with ECM / PCM; DTC U0129: Lost Communication with Brake System Control Module; DTC U0142: Lost Communication with Main Body ECU; DTC U0155: Lost Communication with Combination Meter [08/2015 - 08/2019] >> Description
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DTC U0100: Lost Communication with ECM / PCM; DTC U0129: Lost Communication with Brake System Control Module; DTC U0142: Lost Communication with Main Body ECU; DTC U0155: Lost Communication with Combination Meter [08/2015 - 08/2019]: Description

The power management control ECU receives information from 2 sources. It receives information via a direct line and via the CAN communication line. If the information from these 2 sources is inconsistent, this DTC is stored.

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 is reset to on (IG). When the battery is removed and reinstalled, the power source mode that was selected when the battery was removed is restored.

DTC Code DTC Detection Condition Trouble Area
U0100 There is no communication from the ECM.
  • CAN communication system
  • ECM
U0142 There is no communication from the main body ECU.
  • CAN communication system
  • Main body ECU (Driver side junction block assembly)
U0129 There is no communication from the skid control ECU.
  • CAN communication system
  • Skid control ECU
U0155 There is no communication from the combination meter.
  • CAN communication system
  • Combination meter assembly
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