Circuit/System Verification
WARNING: This page is about a different car, the 2022 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition - On / Vehicle - In Service Mode
- Verify there are no DTCs set related to the following component/system:
- B74 Manifold Absolute Pressure Sensor
- B75D Multifunction Intake Air Sensor - Bank 1
- B75E Multifunction Intake Air Sensor - Bank 2
- B111B Turbocharger/Supercharger Boost Pressure and Intake Air Temperature Sensor
- 5V Reference Circuit
- Throttle Position Sensor
- If a related DTC is set
- Go to next step: If a related DTC is not set
- Verify the scan tool parameter: Throttle Body Idle Air Flow Compensation = Less than 90%
- If 90% or greater
Refer to: Throttle Body Inspection and Cleaning
- Go to next step: If less than 90%
- If 90% or greater
- Perform the scan tool control function: Throttle Sweep - Start
Verify the scan tool parameter: Throttle Position Sensor and Sensor 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
- If not the specified state
- Verify the scan tool parameter:
- Turbocharger/Supercharger Boost Pressure Sensor = The value should be within the range listed in the table: Altitude Versus Barometric Pressure
- Manifold Absolute Pressure Sensor = The value should be within the range listed in the table: Altitude Versus Barometric Pressure
- If not in the specified range
- {Turbocharger/Supercharger Boost Pressure Sensor} Refer to: DTC P0237 or P0238
- {Manifold Absolute Pressure Sensor} Refer to: DTC P0107 or P0108
- Go to next step: If in the specified range
- Engine - Idling - At normal operating temperature
- Verify the scan tool parameter:
- Manifold Absolute Pressure Sensor = 26 to 52 kPa (3.8 to 7.5 PSI) @ Idle Speed
- Manifold Absolute Pressure 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
- Verify the scan tool parameter: Turbocharger/Supercharger Boost Pressure Sensor = The value should change with accelerator pedal input.
- If the value does not change
Refer to: DTC P0237 or P0238
- Go to next step: If the value changes
- If the value does not change
- Increase the engine speed slowly to 3k RPM and then back to idle.
- Perform the scan tool function: Review Stored Data
- Observe the scan tool parameter frame by frame with a scan tool: Mass Airflow Sensor
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, P0103, P010C, P010D, U060F, U0610, U1319, or U131A
- Go to next step: If the value changes smoothly and gradually
- If the value does not change smoothly and gradually
- Verify the tool is available: GE-52250
Variable Pressure Leak Detector
- If the tool is not available
Refer to step 14
- Go to next step: If the tool is available
- If the tool is not available
- Perform the following procedure/test: Component/System Leak Test
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
- If the procedure/test does not pass
- Verify the following conditions do not exist:
- B74 Manifold Absolute Pressure Sensor - Visible Damage
- B75 Mass Air Flow Sensor - Contamination of the measuring element / Visible Damage/Water intrusion
- B111B Turbocharger/Supercharger Boost Pressure and 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
- 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
NOTE:It may be necessary to use a scan tool control function to operate a component.
- If a condition exists
Repair or replace as necessary
- Go to next step: If no condition exists
- Verify the following conditions do not exist: Engine - Mechanical Condition
- Compressor Air Intake Turbo charger or Turbine 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 Valve or Intake Valve - Stuck Open/Visible Damage
- Exhaust Valve Seat or Intake Valve Seat - Visible Damage
- Piston - Cracked/Visible Damage
- Piston Ring - Seized/Visible Damage/Worn
NOTE:The list is not all encompassing - Refer to: Symptoms - Engine Mechanical
- If a condition exists
Repair or replace as necessary
- Go to next step: If no condition exists
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
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
- If the DTC sets
- All OK.