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Home/DTC Codes/Toyota/4Runner/2003-2009 4.7L V8/U0243
U0243

Lost Communication with Trailer Hitch Module

2003-2009 Toyota 4Runner 4.7L V8

Low SeverityNetworkGeneric (SAE)

Description

Cannot communicate with the integrated trailer hitch control module.

Symptoms

  • Trailer lights not working
  • Trailer brake output disabled
  • Tow/haul mode limited
  • Trailer sway control disabled

Common Causes

  • Hitch module failure
  • CAN bus wiring
  • Module power loss
  • Fuse blown
  • Trailer connector corrosion

Diagnostic Steps

  1. Check hitch module fuse
  2. Test power and ground
  3. Check CAN wiring
  4. Inspect trailer connector
  5. Test trailer light outputs

Repair Notes

Check fuses and trailer connector. Corrosion at trailer plug is the most common cause.

Related Codes

U0130Lost Communication with Trailer Brake Control Module

Other Network Codes

U0243 on Other Vehicles

Toyota 4Runner

2003-2009 4.0L V6

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2010-2024 4.0L V6

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2023-2025 2.4L I4 Turbo T24A-FTS

Toyota Alphard

2023-2025 2.5L I4 Hybrid A25A-FXS

Toyota Altezza

1998-2005 2.0L I4 3S-GE BEAMS

Toyota Altezza

1998-2005 2.0L I6 1G-FE

Toyota Aqua

2011-2021 1.5L I4 Hybrid 1NZ-FXE

Common Questions

What does code U0243 mean on a 2003-2009 Toyota 4Runner?

U0243 stands for "Lost Communication with Trailer Hitch Module". Cannot communicate with the integrated trailer hitch control module.

What are the symptoms of U0243 on a Toyota 4Runner?

Common symptoms of U0243 include: Trailer lights not working, Trailer brake output disabled, Tow/haul mode limited, Trailer sway control disabled.

What causes U0243 on a 2003-2009 Toyota 4Runner?

Common causes of U0243 include: Hitch module failure, CAN bus wiring, Module power loss, Fuse blown, Trailer connector corrosion.

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