U1858 Code - Electronic Brake Control Module Lost Communication With Hybrid/EV Powertrain Control Module On Chassis Expansion CAN Bus
Quick Answer
The Drive Motor Control Modules and the Hybrid/EV Powertrain Control Module 1 are all internal to the Power Inverter Module. Common causes include 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. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- U1858 indicates Electronic Brake Control Module Lost Communication With Hybrid/EV Powertrain Control Module On Chassis Expansion CAN Bus.
- Common causes
- Common causes include 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.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code U1858 Description
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.
What are the Possible Causes of the DTC U1858?
- 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 to Fix the DTC U1858?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the U1858 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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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
Frequently Asked Questions about U1858 Code
1. What are the common symptoms of OBDII code U1858?
- The common symptoms include the illumination of the Check Engine Light, ABS warning light, and potential issues with the electronic brake control system.
2. What could cause the OBDII code U1858 to trigger?
- The code U1858 is triggered when there is a communication loss between the Electronic Brake Control Module (EBCM) and the Hybrid/EV Powertrain Control Module (PCM) on the Chassis Expansion CAN Bus.
3. How can I diagnose the cause of code U1858?
- A thorough diagnostic scan using an OBDII scanner is recommended to pinpoint the exact cause of the communication loss between the EBCM and the Hybrid/EV PCM.
4. What are some possible repair tips for resolving code U1858?
- Check the wiring and connectors between the EBCM and the Hybrid/EV PCM for any damage or loose connections. Resetting the fault codes and retesting the system may also help resolve the issue.
5. Can code U1858 be fixed without professional help?
- While some basic troubleshooting steps can be taken by experienced DIYers, resolving code U1858 may require specialized diagnostic tools and expertise. Seeking professional help is recommended for a comprehensive repair.
6. Is it safe to drive with OBDII code U1858 present?
- It is not recommended to drive with code U1858 present, as it indicates a communication issue between critical control modules that could affect the vehicle's braking system and overall safety.
7. How urgent is it to address OBDII code U1858?
- Addressing code U1858 promptly is important to ensure the proper functioning of the electronic brake control system and avoid potential safety hazards associated with a communication loss between control modules.
8. Can extreme weather conditions cause code U1858 to trigger?
- Extreme weather conditions could potentially contribute to the triggering of code U1858 by affecting the electrical connections and communication pathways between the EBCM and the Hybrid/EV PCM.
9. Are there any recalls related to OBDII code U1858?
- It is advisable to check with the vehicle manufacturer or authorized service centers for any recalls or technical service bulletins related to code U1858, as they may offer solutions or assistance for affected vehicles.
10. How can I prevent OBDII code U1858 from recurring in the future?
- Regular maintenance and inspections of the vehicle's electronic control systems, including the EBCM and Hybrid/EV PCM, can help prevent communication issues that lead to code U1858.
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