OBD Guide

P143A

Reductant Control System Diagnostic Signal Message Counter Incorrect

P143A is an OBD-II diagnostic trouble code meaning: Reductant Control System Diagnostic Signal Message Counter Incorrect. Common causes: malfunction of the reductant system control module, problems with system wiring or connectors. Estimated repair cost: $28–167.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$28–167 (est.)

Symptoms

  • Check Engine light comes on
  • Reduced engine power
  • Increased fuel consumption
  • AdBlue system error message on the dashboard
  • Problems with the exhaust gas cleaning system

Causes

  • Malfunction of the reductant system control module
  • Problems with system wiring or connectors
  • Failures in ECU software
  • AdBlue system sensor malfunction
  • Problems with communication between modules (CAN bus)

How to Fix

  1. Diagnose the AdBlue system using a scanner
  2. Check the integrity of the system wiring and connectors
  3. Update ECU software
  4. Check and, if necessary, replace reagent system sensors
  5. If necessary, replace the reductant system control module

Related codes

FAQ

What does the P143A code mean?

P143A is an OBD-II diagnostic trouble code that indicates: Reductant Control System Diagnostic Signal Message Counter Incorrect

What causes a P143A error code?

The most common causes of P143A include: Malfunction of the reductant system control module; Problems with system wiring or connectors; Failures in ECU software; AdBlue system sensor malfunction.

How do I fix a P143A diagnostic trouble code?

To fix P143A: Diagnose the AdBlue system using a scanner. Check the integrity of the system wiring and connectors. Update ECU software. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P143A?

Yes, but get it checked soon

How much does it cost to fix P143A?

The estimated repair cost for P143A is $28–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat