P006B Code: MAP Exhaust Pressure Correlation

If you have run a code scan and you’re having trouble figuring out what a code P006B means, this short guide should help you get started on your diagnosis.

What Does the P006B Code Mean?

Diagnostic trouble code (DTC) P006B stands for “MAP Exhaust Pressure Correlation.” It is set when the powertrain control module (PCM) detects that the difference between the signals from the manifold absolute pressure (MAP) sensor and the exhaust pressure sensor is beyond specification.

P006B will only appear on vehicles with an exhaust pressure sensor that can be used for a rationality check with the MAP sensor.

The MAP sensor relays information about the amount of pressure present in the engine intake manifold to the PCM. The exhaust pressure sensor, on the other hand, tells the PCM about the amount of pressure in the exhaust manifold. If the PCM perceives that the difference between the signals from these two sensors is beyond specification, the error code P006B is logged.

For more information that can help you properly diagnose and fix P006B, read our technical discussion about intake manifold pressure.

A Quick Note about EBP (Exhaust Backpressure) Sensor

The exhaust gas pressure sensor or exhaust back pressure sensor is a very important component in the diesel particulate filter (DPF) regeneration process on some platforms, but it isn’t present on all. But modern diesel vehicles also use a MAP sensor and when one is compared to the other, code P006B may be output if they don’t correlate.

The exhaust gas pressure sensor or exhaust back pressure sensor is a very important component in the diesel particulate filter (DPF) regeneration process on some platforms, but it isn’t present on all.

– Richard McCuistian, ASE Certified Master Automobile Technician

Note: The definition of code P006B may be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

What are the Possible Causes of the P006B Code?

P006B is a generic code, so it can have several causes. Here are the most common:

• Faulty exhaust pressure sensor
• Faulty MAP Sensor
• Circuit  issues
• Vacuum leak
• PCM failure

What are the Common Symptoms of the P006B Code?

You may notice the following symptoms if you drive a vehicle with a stored P006B trouble code:

• Illuminated check engine light
• Poor engine performance
• Bad fuel mileage
• Excessive smoke from exhaust

How to Diagnose the P006B Code

To avoid potential engine complications, code P006B should be resolved immediately. Diagnosing this code can get tricky though, as it has several possible causes.

As a rule of thumb, always follow the diagnostic procedure specified by your vehicle’s manufacturer. This is because the process may differ per vehicle. For example, the steps for diagnosing a code P006B on a Ford may differ from the steps for testing a GM P006B code.

Refer to a vehicle-specific repair manual for the appropriate diagnostic strategy. If you’re not well-versed in auto repair, it would be best to leave the job to a mechanic.

How to Fix the P006B Code

Like other OBD-II codes, there is no fixed solution for a P006B code. All vehicles are different, so you should always refer to your vehicle’s factory repair information before DIY-ing any repairs. 

Code P006B is a complicated code, so always consult a repair manual or repair database before attempting to resolve it. If you’re not that confident in your automotive repair skills, you should consider enlisting the help of a professional.

Products Mentioned in this Guide

MAP Sensor Intake Manifold