OBD Guide

P21F7

Fuel Control System B Too Rich Off Idle Bank 2

P21F7 is an OBD-II diagnostic trouble code meaning: Fuel Control System B Too Rich Off Idle Bank 2. Common causes: oxygen sensor malfunction (bank 2), fuel leaking from injectors. Estimated repair cost: $17–89.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$17–89 (est.)

Symptoms

  • Increased fuel consumption
  • Unstable engine operation
  • Black smoke from the exhaust pipe
  • Reduced engine power
  • Check Engine Light Illuminates

Causes

  • Oxygen sensor malfunction (bank 2)
  • Fuel leaking from injectors
  • Problems with the fuel pressure regulator
  • Contamination or malfunction of the air flow sensor
  • EVAP system malfunction

How to Fix

  1. Check the condition of oxygen sensors (bank 2)
  2. Diagnose fuel injectors for leaks
  3. Check fuel pressure regulator
  4. Clean or replace the mass air flow sensor
  5. Check the EVAP system for leaks

Related codes

Error P21F7 by Vehicle Brand

FAQ

What does the P21F7 code mean?

P21F7 is an OBD-II diagnostic trouble code that indicates: Fuel Control System B Too Rich Off Idle Bank 2

What causes a P21F7 error code?

The most common causes of P21F7 include: Oxygen sensor malfunction (bank 2); Fuel leaking from injectors; Problems with the fuel pressure regulator; Contamination or malfunction of the air flow sensor.

How do I fix a P21F7 diagnostic trouble code?

To fix P21F7: Check the condition of oxygen sensors (bank 2). Diagnose fuel injectors for leaks. Check fuel pressure regulator. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P21F7?

Yes, but get it checked soon

How much does it cost to fix P21F7?

The estimated repair cost for P21F7 is $17–89. Actual cost depends on your vehicle, location, and labor rates.

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