CAN network

U0117 — Lost Communication with PTO Control Module

Severity: medium Safe to drive

What U0117 means

U0117 means one or more control units stopped receiving messages from the power take-off (PTO) control module over the CAN bus. This module is found on commercial and work trucks, where it engages the PTO that drives a hydraulic pump, winch, crane or other equipment. When the module goes silent, the network flags a lost-communication fault and stores the code.

Symptoms

  • PTO will not engage
  • Hydraulic pump or other PTO-driven equipment is dead
  • Warning lamps on the dash
  • Functions of the affected module unavailable
  • Other U-code communication faults stored

Possible causes

  1. Failed PTO control module
  2. Open, shorted or chafed CAN bus wiring
  3. Corroded connectors or terminals
  4. Power supply or ground fault at the module
  5. Another faulty module loading down the CAN bus
  6. Clutch interlock circuit fault tied to PTO engagement

How to diagnose

  1. Run a full-module scan to map which modules do and do not communicate
  2. Look for other lost-communication codes and blown fuses
  3. Inspect the PTO module connectors and harness for chafing, moisture and corrosion
  4. Test the module's power and ground with a multimeter
  5. Measure CAN bus resistance and CAN-H/CAN-L voltages at the diagnostic connector
  6. Check the clutch interlock circuit if it is part of PTO engagement
  7. Unplug suspect modules one at a time, only following a documented procedure

Common fixes

  • Repair the damaged wiring or replace the connector
  • Clean corroded terminals and restore the ground connection
  • Replace the PTO module and program it as required
  • Fix the faulty module that is loading the CAN bus
  • Repair the clutch interlock circuit

Questions and answers

Can I drive with a U0117 code?

Usually yes, since basic driving is not affected. However, the PTO and attached equipment will not work, and bus problems can sometimes disturb other functions.

What most often causes U0117?

Most often it is CAN wiring or connector trouble, or a lost power or ground at the module. The PTO module itself fails less often, so start with inspection and voltage checks.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.