Faulty manifold absolute pressure (MAP) sensor or its wiring; Faulty exhaust pressure sensor or its wiring; Clogged or restricted exhaust pressure sensor port or tube; Vacuum leak or intake leak affecting MAP sensor reading; Exhaust restriction (e.g., clogged diesel particulate filter) altering exhaust pressure; Corroded or damaged connector pins at either sensor; PCM software issue or internal fault (rare)

DTC codes / P00xx · Fuel and air metering and auxiliary emission controls / P006B

P006BMAP - Exhaust Pressure Correlation

Q: What does code P006B mean?

MAP - Exhaust Pressure Correlation. P006B indicates that the powertrain control module (PCM) has detected a poor correlation between the manifold absolute pressure (MAP) sensor signal and the exhaust pressure sensor signal during key-on engine-off or low-load conditions. The computer expects these two pressure readings to track closely when the engine is not running or under specific operating states, and a deviation beyond the calibrated threshold triggers this code.

P006B indicates that the powertrain control module (PCM) has detected a poor correlation between the manifold absolute pressure (MAP) sensor signal and the exhaust pressure sensor signal during key-on engine-off or low-load conditions. The computer expects these two pressure readings to track closely when the engine is not running or under specific operating states, and a deviation beyond the calibrated threshold triggers this code.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering and auxiliary emission controls

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Rough idle or unstable engine speed if the MAP sensor is faulty
Reduced engine performance or poor fuel economy due to incorrect load calculation
Black smoke or rich running condition if the exhaust pressure sensor is skewed
Intermittent stalling or hesitation during acceleration in some cases

Common causes, most likely first

Faulty manifold absolute pressure (MAP) sensor or its wiring
Faulty exhaust pressure sensor or its wiring
Clogged or restricted exhaust pressure sensor port or tube
Vacuum leak or intake leak affecting MAP sensor reading
Exhaust restriction (e.g., clogged diesel particulate filter) altering exhaust pressure
Corroded or damaged connector pins at either sensor
PCM software issue or internal fault (rare)

How to diagnose and fix it

Verify the code with a scan tool and check for any related pending or stored codes
Inspect the MAP sensor and exhaust pressure sensor connectors for corrosion or damage
Check the exhaust pressure sensor tube or port for blockage or soot buildup and clean if necessary
Compare live MAP and exhaust pressure readings during key-on engine-off to see if they match within specification
Perform a visual inspection for vacuum leaks or exhaust restrictions that could skew readings
Test the MAP sensor and exhaust pressure sensor with a multimeter or oscilloscope if readings are inconsistent
Replace the faulty sensor or repair wiring as needed, then clear codes and verify the repair

What most technicians overlook with P006B

A clogged exhaust pressure sensor port is a frequent cause on diesel vehicles, and cleaning it often resolves the code without replacing any parts.
The MAP and exhaust pressure sensors may share a common ground or reference voltage, so a wiring fault in one circuit can affect both readings.
This code can set intermittently due to a sticking exhaust pressure sensor, so a live data comparison during key-on engine-off is more reliable than a static resistance check.
Some vehicles use the exhaust pressure sensor only for diesel particulate filter monitoring, and a faulty sensor may not produce any driveability symptoms until regeneration is affected.
After replacing a sensor, a relearn or adaptation reset may be required on certain models to prevent the code from returning.

Can I keep driving with P006B?

The vehicle is generally safe to drive with P006B, but avoid heavy acceleration or towing until the fault is diagnosed, as incorrect pressure readings can affect fuel delivery and emissions control. If the check engine light flashes or performance degrades noticeably, stop driving and seek professional service.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.