OBD Guide

P21B0

Reductant Level Sensor C Circuit High

P21B0 is an OBD-II diagnostic trouble code meaning: Reductant Level Sensor C Circuit High. Common causes: short circuit in the sensor circuit, reductant level sensor malfunction. Estimated repair cost: $33–89.

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

Symptoms

  • Check Engine light comes on
  • Reduced engine power
  • Increased fuel consumption
  • Possible transition to emergency mode
  • SCR error message on instrument panel

Causes

  • Short circuit in the sensor circuit
  • Reductant level sensor malfunction
  • Wiring Harness Problems
  • Contact corrosion
  • SCR control module malfunction

How to Fix

  1. Check the integrity of the sensor wiring harness
  2. Check connections and contacts for corrosion
  3. Test the reductant level sensor
  4. Check the voltage in the circuit
  5. Replace sensor if necessary

Related codes

Error P21B0 by Vehicle Brand

FAQ

What does the P21B0 code mean?

P21B0 is an OBD-II diagnostic trouble code that indicates: Reductant Level Sensor C Circuit High

What causes a P21B0 error code?

The most common causes of P21B0 include: Short circuit in the sensor circuit; Reductant level sensor malfunction; Wiring Harness Problems; Contact corrosion.

How do I fix a P21B0 diagnostic trouble code?

To fix P21B0: Check the integrity of the sensor wiring harness. Check connections and contacts for corrosion. Test the reductant level sensor. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P21B0?

Yes, but get it checked soon

How much does it cost to fix P21B0?

The estimated repair cost for P21B0 is $33–89. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat