OBD Guide

P2042

Reductant Temperature Sensor A Circuit

P2042 is an OBD-II diagnostic trouble code meaning: Reductant Temperature Sensor A Circuit. Common causes: reagent temperature sensor malfunction, 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 comes on
  • Reduced engine power
  • Increased fuel consumption
  • Increased NOx emissions
  • SCR system error message on dashboard

Causes

  • Reagent temperature sensor malfunction
  • Open or short circuit in the sensor circuit
  • Poor contact in sensor connectors
  • Wiring harness damage
  • SCR control module malfunction

How to Fix

  1. Check the continuity of the temperature sensor circuit
  2. Check sensor connectors and contacts
  3. Check sensor resistance at different temperatures
  4. Replace reagent temperature sensor if necessary
  5. Check the operation of the SCR control module

Related codes

Error P2042 by Vehicle Brand

FAQ

What does the P2042 code mean?

P2042 is an OBD-II diagnostic trouble code that indicates: Reductant Temperature Sensor A Circuit

What causes a P2042 error code?

The most common causes of P2042 include: Reagent temperature sensor malfunction; Open or short circuit in the sensor circuit; Poor contact in sensor connectors; Wiring harness damage.

How do I fix a P2042 diagnostic trouble code?

To fix P2042: Check the continuity of the temperature sensor circuit. Check sensor connectors and contacts. Check sensor resistance at different temperatures. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P2042?

Yes, but get it checked soon

How much does it cost to fix P2042?

The estimated repair cost for P2042 is $28–89. Actual cost depends on your vehicle, location, and labor rates.

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