U0134

Lost Communication With Power Steering Control Module Rear

Network / Communication Network/Communication CAN Bus Communication 🟡 Moderate — Fix within a week ⚠️ Drive with Care
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What This Actually Means

In plain language — no jargon

Your vehicle's main computer lost contact with the rear power steering control module, like a walkie-talkie losing signal. Without this communication, the steering system can't function properly and may become stiff or unresponsive.

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Symptoms You May Notice

3 known symptoms for this code
Stiff or heavy steering wheel with increased effort required
Power steering warning light illuminated on dashboard
Steering assistance intermittently cuts in and out
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How Your ECU Detects This

Technical sensor logic and voltage thresholds

The ECU continuously attempts CAN bus communication with the rear power steering module at regular intervals. It monitors for acknowledgment signals and bus voltage levels to confirm the module is present and responsive. Loss of signal for a defined duration triggers this fault.

Voltage & Parameter Thresholds

ParameterNormal RangeFault Condition
CAN Bus Message Response Time < 100 milliseconds > 500 milliseconds or no response
CAN Bus Voltage 2.5 to 3.5 volts nominal < 1.0 volt or bus shorted to ground
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Diagnostic & DIY Fix Guide

Check these in order — from cheapest to most complex
1
CAN Bus Connectors and Wiring
Inspect all CAN bus connectors between main ECU and rear steering module for corrosion, loose pins, or damaged terminals and reseat firmly.
2
Battery and Ground Connections
Check main battery terminals and engine ground straps for corrosion or looseness, as poor grounding disrupts CAN communication.
3
Rear Power Steering Control Module
If connectors are clean and tight, the module itself may be faulty and require replacement by a dealer.
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When to See a Professional Mechanic

Not all fault codes are safe to DIY

Code U0134 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.
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How to Clear Code U0134

What happens after you fix the fault

Once the fault is repaired, U0134 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.