U0117

Lost Communication With PTO Control Module

Network / Communication Network/Communication CAN Bus Communication Loss 🟡 Moderate — Fix within a week ⚠️ Drive with Care
💬

What This Actually Means

In plain language — no jargon

Your vehicle's main computer has lost its connection to the Power Take-Off (PTO) control module, similar to a walkie-talkie losing signal. This usually affects commercial or specialty vehicles that use PTO for auxiliary equipment like pumps or compressors.

⚡

Symptoms You May Notice

3 known symptoms for this code
PTO equipment not responding or shutting down unexpectedly
Warning light or fault indicator on dashboard
Loss of communication error messages in vehicle display
🔬

How Your ECU Detects This

Technical sensor logic and voltage thresholds

The ECU continuously monitors the CAN bus network for valid communication signals from the PTO control module at regular intervals. When no response or acknowledgment is received within the expected timeframe, a communication loss is flagged. The ECU measures response time and signal integrity to detect breaks in the data link.

Voltage & Parameter Thresholds

ParameterNormal RangeFault Condition
PTO Module Response Time Within 100-500 milliseconds No response or timeout exceeds 1-2 seconds
CAN Bus Signal Integrity Valid checksums and proper message format Corrupted frames or missing heartbeat messages
🔧

Diagnostic & DIY Fix Guide

Check these in order — from cheapest to most complex
1
CAN Bus Connector and Wiring
Inspect all CAN bus connections to the PTO module for corrosion, loose pins, or damaged wiring and reseat connections.
2
PTO Control Module Fuse
Locate and check the PTO module fuse in the fuse panel; replace if blown or corroded.
3
PTO Control Module
If connections are clean and fuse is good, the PTO module itself may need replacement or reprogramming.
⚠️

When to See a Professional Mechanic

Not all fault codes are safe to DIY

Code U0117 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.

Safety note: OBD-II codes identify the system or circuit where a fault was detected — they do not always identify the exact failed component. A professional mechanic using live sensor data will diagnose the root cause more accurately than replacing parts based on the code alone.
🔄

How to Clear Code U0117

What happens after you fix the fault

Once the fault is repaired, U0117 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.

The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.

✅ Safe to Clear When
  • Fault has been diagnosed and repaired
  • You want to confirm the repair worked
  • Code appeared after a sensor was cleaned
⚠️ Do Not Clear When
  • Preparing for an emissions/PUC test
  • Root cause is still undiagnosed
  • Check engine light is flashing
Emissions test note: Clearing codes resets OBD readiness monitors. Most vehicles need 50–100 km of mixed driving before monitors complete. Do not clear codes immediately before an emissions or PUC inspection.