SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSCHEVROLET2008CHEVY EXPRESS G2500, VAN CARGO, 6.6 6REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1801 (ENGINE CONTROLS AND FUEL - 4.4L - DTC P0010 TO DTC P0158)DTC P0068 OR P0121CIRCUIT/SYSTEM DESCRIPTION
2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6

Circuit/System Description

2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6SECTION Circuit/System Description
WARNING: This page is about a different car, the 2009 Cadillac STS. However, it is still accessible from the selected car via links, so may be relevant.

The actual throttle position and airflow rate is compared to an expected throttle position and airflow rate based on engine load. The engine control module (ECM) determines engine load based on inputs from the mass air flow (MAF) sensor and the manifold absolute pressure (MAP) sensor. Further comparisons are done to distinguish if a sensor is at fault, and the respective DTC will set.

The ECM uses the following information to calculate an expected airflow rate:

  • The throttle position (TP)
  • The barometric pressure (BARO)
  • The manifold absolute pressure (MAP)
  • The supercharger inlet absolute pressure (SCIAP)
  • The intake air temperature (IAT)
  • The engine RPM
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready ToolsFree Quote CheckQuote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.