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P0033 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.

Definition

P0033 is an OBD-II Code that refers to Turbocharger or Supercharger Bypass Valve Control Circuit

Meaning

This code has a different meaning for each car's ECU due to the system's design. This generally implies there is an issue with the bypass mechanism for the turbocharger or supercharger, which relieves pressure fully or partially depending on how the system is set up.

Causes

Common causes for this code include:

  • Faulty turbocharger or supercharger bypass valve
  • Faulty Turbocharger Bypass Valve (TVV) Solenoid
  • Intermittent open/short in the TVV wiring harness (solenoid)
  • Intermittent short in PCM ground circuit causing this code to set
  • Failing PCM that does not control the bypass valve anymore, resulting in high engine RPM

Symptoms

The symptoms of a P0033 code are:

  • The Check Engine Light will come on indicating a problem with the system.
  • If the bypass valve and turbo or supercharger are unable to be controlled, they will operate erratically, causing a loss of power or jerking when accelerating.
  • The ECM recognizes that the bypass valve control circuit is intermittent and stops functioning at times.

Diagnosis

To diagnose a P0033 DTC code, a technician would:

1. Use a scan tool to clear all codes and test the system to see if P0033 is still present.

2. Perform a "live data" readout of the turbocharger or supercharger bypass valve control circuit.

3. Compare live data with manufacturer's specifications to see if there are any abnormalities.

4. If no abnormality is detected in the live data, use a test light to check harness continuity and resistance within the wiring harness for turbocharger or supercharger solenoid.

5. A boost pressure test may be required by the manufacturer to determine if the boost pressure is within the recommended range.

6. If the pressure is too low, inspect the intake hoses and pipes for leaks.

7. If the pressure is too high, the bypass valve should be examined. Depending on the manufacturer, bypass valves are either spring powered or diaphragm operated with an electric sensor and control system.

Common mistakes

The following are common mistakes when diagnosing the trouble code P0033:

  • Not checking for intake leaks after the turbocharger to the intake throttle valve is important. There is frequently just a hose or clamp loose, which is causing a loss of pressure.
  • The most typical mistake with this code is to presume that basic components are in working order.
  • Replacing a turbocharger or supercharger too early in the diagnosing process.

How serious is this?

A car with a P0033 trouble code presents a potentially dangerous situation for the vehicle owner, as it can cause power loss or jerking when accelerating. In this case, no degree of repair is too early.

If the engine RPM is frequently at high revs and without any other symptoms, you should have your car's PCM checked immediately to identify the root of the problem.

Turbochargers and superchargers that are not properly isolated from pressure buildups may be damaged irreparably due to intermittent high pressures in the intake manifold. This often occurs if there is an undetected leak in one of the hoses or pipes connecting components within the system, which reduces their ability to function properly.

What repairs can fix the code?

The following are solutions that may fix this problem:

  • If the pressure is in the proper range as indicated by the manufacturer, the pressure sensor is to blame.
  • Between the turbocharger and intake throttle valve, do a pressure test to ensure that the pressure is correct. This will show whether the pressure is too low or excessive as set by the manufacturer.
  • If the pressure is too great, check for a faulty bypass valve to ensure it will open under maximum boost pressure according to the manufacturer's requirements. This generally necessitates either replacing the valve or the actuator on a diaphragm operated system.
  • If the pressure is too low, inspect the intake hoses, intercooler, pipes, and clamps for cracks or looseness. If they are in good working order, check the bypass valve to see if it is slightly or completely open.

Related codes

A P0027 is related to and may be accompanied by the following codes:

  • P0011: Manifold Absolute Pressure (MAP) Sensor Circuit Low Voltage
  • P0012: MAP Sensor Circuit High Voltage
  • P0107: Intake Air Temperature (IAT) Sensor Circuit Intermittent High Voltage
  • P0108: IAT Sensor Circuit Intermittent Low Voltage
  • P0325: Turbo/Super Charger Bypass Valve Control Circuit Malfunction – Open Load – Potentially Bank 1 or 2

How much does it cost to fix the P0033 code?

The repair cost of a P0033 code varies depending on the type of problem.

If it is a loose connection or hose, it can be repaired by tightening the fitting or replacing the damaged component. This may cost between $100 and $400 depending on whether turbocharger or supercharger replacement is required.

For wiring harness problems, you should expect to pay between $100 and $300 to replace the wiring harness if it has any damage caused by frayed insulation or bare wires that are touching other components.

A faulty pressure sensor will generally need to be replaced with a new one, which will cost an average of around $250 for parts alone at most automotive repair shops.

Check for any additional codes that appear before deciding on repairs because these could indicate additional problems that will cost more to fix.

Conclusion

In conclusion, the P0033 code is a trouble code that may occur as a result of problems within the intake manifold pressure sensor, throttle body, wiring harness or turbocharger. It is best to check all parts and connections thoroughly before replacing the pressure sensor itself as this will save time and money.

If you can take care of these things before taking your car to be fixed, it could potentially save hundreds of dollars for you.

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