Circuit/System Verification

• B74 Manifold Absolute Pressure Sensor
• B75C Multifunction Intake Air Sensor
• B111B Turbocharger Boost/Intake Air Temperature Sensor
• 5V Reference Circuit
• Throttle Position Sensor@Q38 Throttle Body

• If a related DTC is set 

  Refer to: Diagnostic Trouble Code (DTC) List - Vehicle

• Go to next step: If a related DTC is not set 

• If 90% or greater 

  Refer to: Throttle Body Cleaning

• Go to next step: If less than 90% 

Verify the scan tool parameter: Throttle Position Sensors 1 and 2 = Agree

• If not the specified state 

  Refer to: DTC P0122, P0123, P0222, P0223, P2135, U0606, or U0607 

• Go to next step: If the specified state 

• Boost Pressure Sensor = The value should be within the range listed in the table: Altitude Versus Barometric Pressure
• MAP Sensor = The value should be within the range listed in the table: Altitude Versus Barometric Pressure

• If not in the specified range 

• {Boost Pressure Sensor} Refer to: DTC P0237 or P0238
• {MAP Sensor} Refer to: DTC P0107 or P0108 

• Go to next step: If in the specified range 

• MAP Sensor = 26 to 52 kPa (3.8 to 7.5 PSI) @Idle Speed
• MAP Sensor = The value should change with accelerator pedal input.

• If not between 26 and 52 kPa (3.8 and 7.5 PSI) or does not change 

  Refer to: DTC P0107 or P0108 

• Go to next step: If between 26 and 52 kPa (3.8 and 7.5 PSI) and changes 

• If the value does not change 

  Refer to: DTC P0237 or P0238

• Go to next step: If the value changes 

Verify the parameter changes smoothly and gradually in the recorded data as the engine speed was increased and decreased.

• If the value does not change smoothly and gradually 

  Refer to: DTC P0102 or P0103 

• Go to next step: If the value changes smoothly and gradually 

• If the tool is not available 

  Refer to step 14

• Go to next step: If the tool is available 

Verify the procedure/test passes.

• If the procedure/test does not pass 

  Repair or replace as necessary

• Go to next step: If the procedure/test passes 

• B74 Manifold Absolute Pressure Sensor - Visible Damage
• B75C Multifunction Intake Air Sensor - Contamination of the measuring element/Visible Damage/Water intrusion
• B111B Turbocharger Boost/Intake Air Temperature Sensor
  • Restricted - Moisture/Ice
  • Skewed
• Q38 Throttle Body
  • Coking/Loose Clamps/Visible Damage
  • Restricted - Moisture/Ice
• Air Cleaner Element - Dirty/Restricted
• Catalytic Converter & Exhaust System - Blocked/Leaking/Restricted/Visible Damage - Refer to: Symptoms - Engine Exhaust
• Charge Air Cooler - Restricted/Moisture/Ice
• Intake Air Duct - Collapsed/Restricted/Visible Damage
• Intake Manifold - Restricted/Visible Damage
NOTE:

It may be necessary to use a scan tool control function to operate a component.

• Linkage@Turbocharger Wastegate Actuator - Binding or Sticking/Loose/Visible Damage
• Q40 Turbocharger Bypass Valve Solenoid - Binding or Sticking/Loose/Visible Damage
• Q42 Turbocharger Wastegate Solenoid Valve - Binding or Sticking/Loose/Visible Damage
• Positive Crankcase Ventilation System - Restricted - Moisture/Ice

• If a condition exists 

  Repair or replace the components as necessary.

• Go to next step: If no condition exists 

NOTE:

The list is not all encompassing - Refer to: Symptoms - Engine Mechanical

• Compressor Air Intake TurbochargerorTurbine Shaft Seal - Leaking - Engine Oil
• Compressor Air Intake Turbocharger - Low oil pressure
• Compressor Air Intake Turbocharger - Mechanical Condition/Worn
• Camshaft Lobe(s) - Visible Damage/Worn
• Exhaust ValveorIntake Valve - Stuck Open/Visible Damage
• Exhaust Valve SeatorIntake Valve Seat - Visible Damage
• Piston - Cracked/Visible Damage
• Piston Ring - Seized/Visible Damage/Worn

• If a condition exists 

  Repair or replace as necessary

• Go to next step: If no condition exists 

Verify the DTC does not set.

• If the DTC sets 

  Repeat the procedure starting at step 1

• Go to next step: If the DTC is not set