Fuel and air

P00B8 — MAP and Mass Airflow Sensor Correlation Fault (Bank 2)

Severity: medium Drive with care, to a shop

What P00B8 means

The engine control unit compares the air mass reported by the MAF sensor with manifold pressure from the MAP sensor and engine speed. At any given operating point these readings should agree. P00B8 sets when they differ by more than the allowed amount for Bank 2. That points to a bad sensor reading or air entering the intake where it should not.

Symptoms

  • Check Engine light on
  • Rough or unstable idle
  • Hesitation or stumbling on acceleration
  • Reduced power and sluggish throttle response
  • Poor fuel economy
  • Possible stalling at idle
  • Abnormal fuel trim values

Possible causes

  1. Dirty or faulty MAF sensor
  2. Failed MAP sensor
  3. Vacuum or intake air leak after the MAF sensor
  4. Damaged wiring or a poor connector in the MAP/MAF circuits
  5. Badly clogged air filter
  6. Rarely, an ECM software fault or internal failure

How to diagnose

  1. Scan all codes and review freeze frame data for other fuel mixture codes
  2. Inspect the air filter and the intake duct between the MAF and throttle body for cracks and loose clamps
  3. Check vacuum hoses and intake manifold gaskets for leaks
  4. Inspect MAP and MAF connectors and wiring, and check power and ground
  5. Compare live MAF and MAP readings at idle and under load with expected values
  6. Check short-term and long-term fuel trims for each bank
  7. Clean the MAF element with proper cleaner and recheck readings
  8. If everything checks out, evaluate the ECM and look for software updates

Common fixes

  • Clean or replace the MAF sensor
  • Replace the faulty MAP sensor
  • Repair intake and vacuum leaks and replace damaged hoses or ducts
  • Repair wiring or connector faults
  • Replace the air filter
  • Reprogram or replace the ECM (rare)

Questions and answers

What does P00B8 mean?

It means the MAP sensor and the mass airflow reading do not agree for Bank 2. The control unit sees pressure and airflow values that do not match.

Can I drive with P00B8?

Short trips to a shop are usually fine, but the engine may run roughly and use more fuel. Do not put off diagnosis for long.

What most often causes P00B8?

A dirty MAF sensor, a failed MAP sensor or an intake air leak are the usual causes. Start by checking the intake ducting and cleaning the MAF.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.