P0033
DTC P0033
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC P0033
- Supercharger Bypass Valve Solenoid Control Circuit
Diagnostic Fault Information
Circuit Description
Supercharger boost pressure is regulated to prevent engine and drive train damage. When the engine is operating under high boost conditions, the Engine Control Module (ECM) limits boost pressure to 82.7 kPa (12 psi) or less. The ECM disables boost under the following conditions:
* Reverse gear is selected
* Electronic throttle control fault is detected.
* An intercooler pump failure is detected
* Intake Air Temperature (IAT) sensor 2 becomes excessively high, equal to or greater than 120.5°C (248°F) boost pressure is limited to 145 kPa (7 psi). ECM commands the boost control solenoid to 62 % duty cycle.
* Engine Coolant Temperature (ECT), is equal to or greater than 125°C (257°F).
* Drivetrain abuse is detected
* Vehicle speeds exceed 256 km/h (159 mph) in third and fourth gears. After 150 s boost is limited to a predetermined threshold.
The ECM controls boost pressure by pulse width modulation of the boost control solenoid. The boost control solenoid is a normally open valve. Under most conditions, the ECM commands the boost control solenoid to operate at a 99-100 % duty cycle. This keeps the boost control solenoid valve closed and allows only inlet vacuum from the supercharger plenum to the bypass valve actuator to control the position of the bypass valve. At idle, engine vacuum is applied to the upper side of the bypass valve actuator, counteracting spring tension to hold the bypass valve open. When the engine load is increased, the engine vacuum is decreased, causing the spring in the bypass valve actuator to overcome the diminishing applied vacuum, closing the bypass valve and allowing the boost pressure to increase. When reduced boost pressure is desired, the ECM commands the boost control solenoid to operate at a 0-98 % duty cycle. This opens the solenoid valve and allows boost pressure to enter the bypass valve actuator at the lower side to counteract the spring tension, opening the bypass valve and recirculating excess boost pressure back into the supercharger inlet.
The ECM monitors the voltage level on the boost control solenoid control circuit.
Conditions for Running the DTC
* The ignition is ON.
OR
* The engine is running.
* The ignition 1voltage is between 11-18 V.
* This DTC runs continuously within the enabling conditions.
Conditions for Setting the DTC
The ECM detects an improper voltage level on the boost control solenoid control circuit for greater than 20 s.
Action Taken When the DTC Sets
DTC P0033 is a Type B DTC.
Conditions for Clearing the MIL/DTC
DTC P0033 is a Type B DTC.
Reference Information
Schematic Reference
Engine Controls Schematics (LS3) ([1][2]Electrical Diagrams)Engine Controls Schematics (LS7) ([1][2]Electrical Diagrams)Engine Controls Schematics (LS9) ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
* Supercharger Description and Operation ()
* Boost Control System Diagnosis ()
* Boost Control System Description ()
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
* Measuring Frequency (Measuring Frequency)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Engine running, command the SCB Solenoid, duty cycle from 0-90 % in 10 % increments with a scan tool. Listen and feel for a clicking at the Q36 supercharger bypass solenoid valve.
2. Engine running, command the SCB Solenoid from None to between 0-10 % with a scan tool while observing the following control circuit status parameters:
* SCB Solenoid Ckt. Short Gnd Test Status
* SCB Solenoid Ckt. Open Test Status
* SCB Solenoid Ckt. Short Volts Test Status
Each parameter should change between OK and Not Run or Not Run and OK.
3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the Q36 supercharger bypass solenoid valve.
2. Ignition ON, verify that a test lamp illuminates between the ignition supply circuit terminal 1 and ground.
• If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
3. Connect a test lamp between the control circuit terminal 2 and the ignition supply circuit terminal 1.
4. Engine running, command the SCB solenoid duty cycle from 0-90 % with a scan tool. The test lamp should change in intensity when incrementing between the commanded states.
• If the test lamp remains ON and does not change in intensity, test the control circuit terminal 2 for a short to ground. If the circuit tests normal, replace the K20 ECM.
• If the test lamp remains OFF, test the control circuit terminal 2 for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
5. If all circuits test normal, test or replace the Q36 supercharger bypass solenoid valve.
Component Testing
Static Test
1. Ignition OFF, disconnect the harness connector at the Q36 supercharger bypass solenoid valve.
2. Test for 30-55 ohm between the control terminal 2 and the voltage supply terminal 1.
• If the resistance is not within the specified range, replace the Q36 supercharger bypass solenoid valve.
Dynamic Test
1. Install a 3 A fused jumper wire between the ignition supply circuit terminal 1 and 12V. Install a jumper wire between the control terminal 2 and ground.
2. Toggle the jumper wire between the control terminal and ground.
3. Feel and listen for the operation of the Q36 supercharger bypass solenoid valve.
• If the function does not perform as specified, replace the Q36 supercharger bypass solenoid valve.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Charge Air Bypass Regulator Solenoid Valve Replacement ()
* Control Module References (Programming and Relearning) for ECM replacement, setup, and programming