OBD Guide

P1018

Reductant Control Module Sensor Communication Voltage Supply Circuit Low Voltage

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Check Engine light comes on
  • Reduced engine power
  • Increased fuel consumption
  • Possible emergency operation of the engine
  • Increased emissions of nitrogen oxides

Causes

  • Open or short circuit in the sensor power supply circuit
  • Faulty reducer module
  • Fuse problems
  • Wiring harness damage
  • Engine ECU malfunction

How to Fix

  1. Check power supply fuses
  2. Inspect the wiring harness for damage
  3. Check the voltage at the reducer module sensor
  4. Test the reductant module
  5. If necessary, replace the module or repair the wiring

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