OBD Guide

U1817

Lost Communication With Hybrid/EV Powertrain Control Module On Powertrain Expansion CAN Bus

U1817 is an OBD-II diagnostic trouble code meaning: Lost Communication With Hybrid/EV Powertrain Control Module On Powertrain Expansion CAN Bus. Common causes: open or short circuit in the can bus circuit, damaged connectors or corroded contacts. Estimated repair cost: $56–278.

Severity
🔴 High
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–278 (est.)

Symptoms

  • Check Engine light comes on
  • Switching to emergency mode
  • Reduced power or hybrid system failure
  • Inability to switch driving modes
  • Errors in the operation of the regenerative braking system

Causes

  • Open or short circuit in the CAN bus circuit
  • Damaged connectors or corroded contacts
  • Malfunction of the hybrid powertrain control module (HPCM)
  • HPCM power supply problems
  • Software failures in control modules

How to Fix

  1. Check the integrity of the CAN bus wiring
  2. Inspect and clean HPCM connectors
  3. Check the supply voltage on the HPCM module
  4. Scan all modules for additional errors
  5. Replace HPCM if necessary
  6. Repair only from an authorized dealer

Related codes

FAQ

What does the U1817 code mean?

U1817 is an OBD-II diagnostic trouble code that indicates: Lost Communication With Hybrid/EV Powertrain Control Module On Powertrain Expansion CAN Bus

What causes a U1817 error code?

The most common causes of U1817 include: Open or short circuit in the CAN bus circuit; Damaged connectors or corroded contacts; Malfunction of the hybrid powertrain control module (HPCM); HPCM power supply problems.

How do I fix a U1817 diagnostic trouble code?

To fix U1817: Check the integrity of the CAN bus wiring. Inspect and clean HPCM connectors. Check the supply voltage on the HPCM module. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U1817?

Limited driving only, diagnose soon

How much does it cost to fix U1817?

The estimated repair cost for U1817 is $56–278. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat