Engine-Codes - Generic - U1858

U1858 - Electronic Brake Control Module Lost Communication With Hybrid/EV Powertrain Control Module On Chassis Expansion CAN Bus

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3  What is this?
Table of contents

U1858 Possible Causes

  • Faulty Hybrid/EV Powertrain Control Module
  • Hybrid/EV Powertrain Control Module harness is open or shorted
  • Hybrid/EV Powertrain Control Module circuit poor electrical connection

How is the U1858 code repair?

Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

What is the cost to diagnose the U1858 code

Labor: 1.0

The cost to diagnose the U1858 code is 1.0 hour of labor. The auto repair's diagnosis time and labor rates vary by location, vehicle's make and model, and even your engine type. Most auto repair shops charge between $75 and $150 per hour.
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Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

U1858 Meaning

The Drive Motor Control Modules and the Hybrid/EV Powertrain Control Module 1 are all internal to the Power Inverter Module. The Drive Motor Control Modules communicate only with the Hybrid/EV Powertrain Control Module 1 which sends out diagnostic trouble code information to other devices regarding the Drive Motor Control Modules. All circuits to the Hybrid/EV Powertrain Control Module 1 and Drive Motor Control Modules are also internal to the Power Inverter Module and replaced as a single component.
Communication diagnostics for the serial data, including device power and ground as well as the wakeup circuits for Drive Motor Control Modules and the Hybrid/EV Powertrain Control Module 1 are all diagnosed from external sources only to the Power Inverter Module connector because any circuit fault condition within the Power Inverter Module will cause a complete replacement.
The Diagnostic Trouble Code (DTC) will set when a supervised periodic message that includes the transmitter device availability has not been received.

More Information

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Information for specific makes

  • U1858 BUICK Electronic Brake Control Module Lost Communication With Hybrid/EV Powertrain Control Module On Chassis Expansion CAN Bus
  • U1858 CADILLAC Electronic Brake Control Module Lost Communication With Hybrid/EV Powertrain Control Module On Chassis Expansion CAN Bus
  • U1858 CHEVROLET Electronic Brake Control Module Lost Communication With Hybrid/EV Powertrain Control Module On Chassis Expansion CAN Bus
  • U1858 GMC Electronic Brake Control Module Lost Communication With Hybrid/EV Powertrain Control Module On Chassis Expansion CAN Bus

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