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2007 GMC Sierra LBZ
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What year of truck you got? Looks like it may be time a new vane position sensor. When you take coolant reservoir cap off is it bubbling?
 

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Former GM Tech and parts
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3,587 Posts
Totally unrelated to your new exhaust, unless you took it out hot rodding after putting it on and then tore it up.... the 2563 and 2564 code could be from a vane position sensor going bad
If its pushing coolant, thats not a good sign- that means its over-pressuring the cooling system... usually caused by a blown head gasket. Or could be a bad cap on the tank...
 

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This is a very good description of the MAP sensor function vs engine boost from the P0234 document - specifically for my 2008 LMM engine. I note that the BARO is determined within the ECM in LMM but was an external and replaceable sensor prior engine families.

Circuit/System Description

The manifold absolute pressure (MAP) sensor measures the pressure inside the intake manifold. Pressure in the intake manifold is affected by turbocharger output, engine speed, accelerator pedal input, ambient air temperature, and barometric pressure (BARO).

A diaphragm within the MAP pressure sensor is displaced by the pressure changes that occur from the varying load and operating conditions of the engine. The sensor translates these changes into electrical resistance. The engine control module (ECM) supplies a regulated 5 volts on the 5-volt reference circuit and a ground on a low reference circuit. The MAP sensor provides a signal voltage to the ECM, relative to boost pressures, on the MAP sensor signal circuit. The ECM converts the signal voltage input to a pressure value.

Under normal operation, the lowest pressure that can exist in the intake manifold is equal to the BARO. This occurs when the vehicle is operated at idle or when the ignition is ON while the engine is OFF. The highest manifold pressures occur when the turbocharger output is high. Manifold pressure can range from 58 kPa (8 psi) when pressures are low to more than 295 kPa (42.7 psi) when pressures are high, depending on the BARO. The MAP pressure sensor has a range of 43-365 kPa (6-53 psi). The ECM diagnoses boost pressures by a calculated predicted value at a predetermined engine load and speed. The ECM then compares the predicted value to the sensor actual input.
 

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