OBD Guide

P016B

Closed Loop Air/Fuel Ratio Control At Limit - System Too Rich

P016B is an OBD-II diagnostic trouble code meaning: Closed Loop Air/Fuel Ratio Control At Limit - System Too Rich. Common causes: malfunction of oxygen sensors, fuel leakage through injectors. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Increased fuel consumption
  • Reduced engine power
  • Black smoke from the exhaust pipe
  • Unstable engine idling

Causes

  • Malfunction of oxygen sensors
  • Fuel leakage through injectors
  • Increased pressure in the fuel rail
  • Dirty or faulty air flow sensor
  • EVAP system malfunction
  • Mechanical engine problems (piston group wear)

How to Fix

  1. Check oxygen sensor readings using a scanner
  2. Check fuel injectors for leaks
  3. Measure the pressure in the fuel rail
  4. Check the condition and readings of the mass air flow sensor
  5. Check the EVAP system for leaks
  6. If necessary, replace faulty components

Related codes

Error P016B by Vehicle Brand

FAQ

What does the P016B code mean?

P016B is an OBD-II diagnostic trouble code that indicates: Closed Loop Air/Fuel Ratio Control At Limit - System Too Rich

What causes a P016B error code?

The most common causes of P016B include: Malfunction of oxygen sensors; Fuel leakage through injectors; Increased pressure in the fuel rail; Dirty or faulty air flow sensor.

How do I fix a P016B diagnostic trouble code?

To fix P016B: Check oxygen sensor readings using a scanner. Check fuel injectors for leaks. Measure the pressure in the fuel rail. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P016B?

Limited driving only, diagnose soon

How much does it cost to fix P016B?

The estimated repair cost for P016B is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat