OBD Guide

P21AD

Reductant Level Sensor C Circuit

P21AD is an OBD-II diagnostic trouble code meaning: Reductant Level Sensor C Circuit. Common causes: reagent level sensor fault c, open or short circuit in the sensor circuit. Estimated repair cost: $28–89.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$28–89 (est.)

Symptoms

  • Check Engine Light Is On
  • Reduced engine power
  • Increased fuel consumption
  • SCR System Error Message
  • Problems starting the engine (in some cases)

Causes

  • Reagent level sensor fault C
  • Open or short circuit in the sensor circuit
  • Poor contact in sensor connectors
  • Problems with the control unit
  • Sensor contamination

How to Fix

  1. Check the integrity of the sensor circuit
  2. Inspect the connectors and contacts of the sensor
  3. Check the functionality of the reagent level sensor
  4. Replace sensor if necessary
  5. Reset the error code and check the system

Related codes

Error P21AD by Vehicle Brand

FAQ

What does the P21AD code mean?

P21AD is an OBD-II diagnostic trouble code that indicates: Reductant Level Sensor C Circuit

What causes a P21AD error code?

The most common causes of P21AD include: Reagent level sensor fault C; Open or short circuit in the sensor circuit; Poor contact in sensor connectors; Problems with the control unit.

How do I fix a P21AD diagnostic trouble code?

To fix P21AD: Check the integrity of the sensor circuit. Inspect the connectors and contacts of the sensor. Check the functionality of the reagent level sensor. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P21AD?

Yes, but get it checked soon

How much does it cost to fix P21AD?

The estimated repair cost for P21AD is $28–89. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat