Diagnostic Instructions
DTC Descriptor
DTC P0033: Supercharger Bypass Valve Solenoid Control Circuit
Diagnostic Fault Information
Supercharger Vacuum Bypass Valve Control Solenoid
Circuit
| Short to Ground
| High Resistance
| Open
| Short to Voltage
| Signal Performance
|
Supercharger Vacuum Bypass Valve Control
| P0033
| P0033
| P0033
| P0033
| --
|
Ignition 1 Voltage
| P0033
| P0033
| P0033
| --
| --
|
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 12 psi or less. The ECM disables boost under the
following conditions:
• | When reverse gear is selected |
• | When an electronic throttle control (ETC) fault is detected. |
• | When an intercooler pump failure is detected |
• | When the 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 percent
duty cycle (DC). |
• | When the engine coolant temperature (ECT), is equal to or greater than 125°C (257°F), or the HOT engine light comes on. |
• | When drivetrain abuse is detected |
• | When vehicle speeds exceed 256 km/h (159 mph) in third and fourth gears, after 150 seconds boost is limited to a predetermined threshold. |
• | When the intake cam phasers are inoperable, boost pressure is limited to 145 kPa (7 psi), ECM commands the boost control solenoid to 62 percent duty cycle. |
The ECM controls boost pressure by pulse width modulation (PWM) 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 percent
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 percent 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 engine is running. |
• | The ignition 1 voltage is between 11-18 volts. |
• | 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 seconds.
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
Connector End View Reference
Component Connector End Views
Description and Operation
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Engine running, command the supercharger vacuum bypass valve control (SCB) solenoid, duty cycle from 0 percent to 90 percent in 10 percent increments with a scan tool. Listen and feel for a clicking at the supercharger SCB solenoid.
- Engine running, command the SCB Solenoid from None to 0 percent, then from 0-10 percent with a scan tool while observing the following 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. |
- 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
- Ignition OFF, disconnect the harness connector at the SCB solenoid.
- 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. |
- Connect a test lamp between the control circuit terminal 2 and the ignition supply circuit terminal 1.
- Engine running, command the SCB solenoid duty cycle from 0 percent to 90 percent with a scan tool. The test lamp should change brightness when incrementing between the commanded states.
⇒ | If the test lamp remains ON all the time, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM. |
⇒ | If the test lamp remains OFF all the time, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM. |
- If all circuits test normal, test or replace the SCB solenoid.
Component Testing
Static Test
- Ignition OFF, disconnect the harness connector at the SCB solenoid.
- Test for 30-55 ohms between the control terminal 2 and the voltage supply terminal 1 at the SCB solenoid.
⇒ | If the resistance is not within the specified range, replace the SCB solenoid. |
Dynamic Test
- Install a 3A fused jumper wire between the ignition supply circuit terminal 2 and 12 volts. Install a jumper wire between the control terminal and ground.
- Toggle the jumper wire between the control terminal 2 and ground.
- Feel and listen for the operation of the SCB solenoid.
⇒ | If the function does not perform as specified, replace the SCB solenoid. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.