Engine

P006B — MAP and Exhaust Pressure Sensor Correlation Fault

Severity: medium Drive with care, to a shop

What P006B means

The engine control module compares intake manifold pressure (MAP sensor) with exhaust pressure. At a given load and boost level, the two readings should stay within an expected relationship. When they drift outside it, the module sets P006B and turns on the check engine light. The cause can be a bad sensor or a real air or exhaust leak.

Symptoms

  • Check engine light on
  • Reduced power and sluggish acceleration
  • Poor fuel economy
  • Rough idle or hesitation
  • Visible exhaust smoke
  • Possible limp mode

Possible causes

  1. Failed MAP sensor
  2. Failed exhaust pressure sensor (often clogged with soot)
  3. Damaged wiring or poor connector contact
  4. Intake air leak or exhaust leak ahead of the sensor
  5. Clogged sensor pressure tube or port
  6. ECM software fault or failure (rare)

How to diagnose

  1. Scan all codes and freeze frame data, and look for related boost or pressure codes
  2. Inspect wiring and connectors at the MAP and exhaust pressure sensors for corrosion, chafing or loose pins
  3. Check sensor power, ground and reference voltage at the connectors
  4. With the key on and engine off, compare both sensor readings: they should be close to atmospheric pressure
  5. Inspect boost hoses, intake pipes and the manifold for air leaks, and check the exhaust for leaks
  6. Check the exhaust sensor's pressure tube for soot buildup and clean it
  7. Compare live readings under load with known good values
  8. If everything checks out, look for an ECM software update

Common fixes

  • Replace the MAP sensor
  • Replace the exhaust pressure sensor or clean its feed tube
  • Repair damaged wiring or connectors
  • Fix intake or exhaust leaks
  • Reflash or replace the ECM (last resort)

Questions and answers

What does P006B mean?

The engine computer sees that the MAP sensor and the exhaust pressure sensor readings do not agree. Either sensor could be at fault, or there may be a leak in the air or exhaust path.

Can I drive with code P006B?

Briefly, yes, but expect possible power loss and higher fuel use. Do not put off diagnosis, especially if you see smoke or the engine stumbles.

How do I fix P006B?

Start with wiring, connectors and leaks, then test the sensors. Replace a sensor only after confirming it is faulty.

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.