OBD Guide

C121E

Brake Pressure Sensor Comparative Performance

C121E is an OBD-II diagnostic trouble code meaning: Brake Pressure Sensor Comparative Performance. Common causes: brake pressure sensor malfunction, problems in the wiring harness. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • ABS/ESP light is on
  • Reduced braking performance
  • Incorrect operation of the stabilization system

Causes

  • Brake pressure sensor malfunction
  • Problems in the wiring harness
  • ABS control unit malfunction
  • Contamination of sensor contacts

How to Fix

  1. Check pressure sensor readings using a diagnostic scanner
  2. Inspect the wiring harness for damage
  3. Check sensor contacts for oxidation
  4. If necessary, replace pressure sensors or ABS control unit

Related codes

FAQ

What does the C121E code mean?

C121E is an OBD-II diagnostic trouble code that indicates: Brake Pressure Sensor Comparative Performance

What causes a C121E error code?

The most common causes of C121E include: Brake pressure sensor malfunction; Problems in the wiring harness; ABS control unit malfunction; Contamination of sensor contacts.

How do I fix a C121E diagnostic trouble code?

To fix C121E: Check pressure sensor readings using a diagnostic scanner. Inspect the wiring harness for damage. Check sensor contacts for oxidation. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with C121E?

Limited driving only, diagnose soon

How much does it cost to fix C121E?

The estimated repair cost for C121E is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat