OBD Guide

P209B

Reductant Injection Air Pressure Sensor B Circuit Range/Performance

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$33–89 (est.)

Symptoms

  • Check Engine Light Is On
  • Reduced engine power
  • Increased fuel consumption
  • Problems starting the engine
  • Changes in the operation of the SCR system

Causes

  • Air pressure sensor B fault
  • Open or short circuit in the sensor circuit
  • Connector problems or contact corrosion
  • SCR control module malfunction
  • Contamination or damage to system air lines

How to Fix

  1. Diagnose the sensor circuit using a scanner
  2. Check the integrity of the wiring and connector contacts
  3. Test the air pressure sensor with a multimeter
  4. If necessary, replace the sensor or repair the wiring
  5. Reset fault code after repair

Related codes

Error P209B by Vehicle Brand