OBD Guide

P2278

O2 Sensor Signals Swapped Bank 1 Sensor 3/Bank 2 Sensor 3

P2278 is an OBD-II diagnostic trouble code meaning: O2 Sensor Signals Swapped Bank 1 Sensor 3/Bank 2 Sensor 3. Common causes: incorrect connection of o2 sensor connectors, damaged or tangled wiring harness. Estimated repair cost: $22–89.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$22–89 (est.)

Symptoms

  • Check Engine Light Is On
  • Slight deterioration in fuel consumption
  • Minor failures in engine operation are possible
  • Increased emissions
  • Possible errors with other O2 sensors

Causes

  • Incorrect connection of O2 sensor connectors
  • Damaged or tangled wiring harness
  • Errors when replacing oxygen sensors
  • Problems with wiring connectors
  • Malfunction of the oxygen sensor itself

How to Fix

  1. Check that the O2 sensor connectors are connected correctly
  2. Inspect the wiring harness for damage
  3. Check the integrity of wiring and connectors
  4. If necessary, replace damaged wires or connectors
  5. If the problem persists, replace the oxygen sensors

Related codes

Error P2278 by Vehicle Brand

FAQ

What does the P2278 code mean?

P2278 is an OBD-II diagnostic trouble code that indicates: O2 Sensor Signals Swapped Bank 1 Sensor 3/Bank 2 Sensor 3

What causes a P2278 error code?

The most common causes of P2278 include: Incorrect connection of O2 sensor connectors; Damaged or tangled wiring harness; Errors when replacing oxygen sensors; Problems with wiring connectors.

How do I fix a P2278 diagnostic trouble code?

To fix P2278: Check that the O2 sensor connectors are connected correctly. Inspect the wiring harness for damage. Check the integrity of wiring and connectors. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P2278?

Yes, but get it checked soon

How much does it cost to fix P2278?

The estimated repair cost for P2278 is $22–89. Actual cost depends on your vehicle, location, and labor rates.

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