OBD Guide
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P126E

Nitrogen Oxide Sensor Trailing Throttle Check Binary Lambda Signal Too Rich

P126E is an OBD-II diagnostic trouble code meaning: Nitrogen Oxide Sensor Trailing Throttle Check Binary Lambda Signal Too Rich. Common causes: nox sensor malfunction, problems with fuel injectors (overflow). Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Increased fuel consumption
  • Poor engine idling
  • Check Engine light comes on
  • Increased emissions of harmful substances
  • Reduced engine power

Causes

  • NOx sensor malfunction
  • Problems with fuel injectors (overflow)
  • Oxygen sensor malfunction
  • Dirty or faulty EGR system
  • Problems with the mass air flow sensor (MAF)

How to Fix

  1. Check the operation of the NOx sensor
  2. Diagnose fuel injectors
  3. Check the oxygen sensor readings
  4. Clean or replace EGR system components
  5. Check the condition of the mass air flow sensor

Related codes

P126FP1270P1271

FAQ

What does the P126E code mean?

P126E is an OBD-II diagnostic trouble code that indicates: Nitrogen Oxide Sensor Trailing Throttle Check Binary Lambda Signal Too Rich

What causes a P126E error code?

The most common causes of P126E include: NOx sensor malfunction; Problems with fuel injectors (overflow); Oxygen sensor malfunction; Dirty or faulty EGR system.

How do I fix a P126E diagnostic trouble code?

To fix P126E: Check the operation of the NOx sensor. Diagnose fuel injectors. Check the oxygen sensor readings. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P126E?

Yes, but get it checked soon

How much does it cost to fix P126E?

The estimated repair cost for P126E is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat