P0039 – Turbo/super charger bypass valve, control circuit range/performance

Benjamin Jerew

By Benjamin Jerew (Contact Me)
Last Updated 2016-06-07
ASE Master Tech

CodeFault LocationProbable Cause
P0039 Turbo/super charger bypass valve, control circuit range/performance
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Wiring, bypass valve

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What Does Code P0039 Mean?

Depending on the aim, automakers may use forced induction, that is, a turbocharger or supercharger, to dramatically boost the performance of an engine. Forced induction on big V6 and V8 engines can bump engine output to over 1,000 hp. The same technique is used on smaller I3 and I4 engines to boost power for acceleration, while the smaller displacement offers exceptional cruising fuel economy. Turbochargers and superchargers both function similarly, in that they compress the air going into the intake, though they are driven differently, turbochargers by the exhaust stream and superchargers by a belt or electric motor. More air equals more oxygen, for which the ECM (engine control module) can inject more fuel, therefore extracting more power out of the engine.


Understandably, the ECM needs to modulate how much compression the forced induction system provides, both for performance as well as to protect the engine itself. The wastegate or bypass valve serves this function, bleeding off excess pressure. A turbocharger wastegate refers to the valve that bleeds off exhaust pressure before it has a chance to spool up the compressor. A bypass valve, which can be used on either turbochargers or superchargers, refers to the valve that bleeds off compressed air in the intake. Either way, intake pressure or boost pressure is limited.

Some vehicles use a vacuum- or pressure-operated modulator to control the bypass valve, while others use an electric solenoid valve to control the bypass valve. On vehicles that use the solenoid valve, the ECM monitors intake pressure, via the MAP (manifold absolute pressure) sensor, modulating the turbocharger bypass valve control solenoid, sometimes called a boost control solenoid (BCS) as needed. It is good to keep in mind that this is a three-piece system. The BCS controls the bypass valve actuator (BVA). The BVA, in turn, controls the boost bypass valve (BBV) inside the turbocharger housing or intake.

If the ECM detects a problem with the BCS circuit, such as an open or short circuit, intermittent connection, or excessive resistance, it cannot control the turbocharger bypass valve. The check engine light (CEL) will illuminate and a diagnostic trouble code (DTC) will be stored in system memory. DTC P0039 is defined as “Turbo/Super Charger Bypass Valve Control Circuit Range/Performance.”


What are the common causes of code P0039 ?

Depending on year, make, and model, DTC P0039 may have number of causes. Here are some of the most common.

  • BCS Failure – Like all electrical components, the solenoid valve is simply an electromagnetic coil of wire, which can fail. This is the most common failure in this instance.
  • Electrical Problems – Open circuits, short circuits, loose connections, and corrosion are all par for the course.

What are the symptoms of code P0039 ?

Normal driving may not be affected by a fault in the BCS, especially if you don’t accelerate very hard. Some vehicles, particularly those driven hard, may experience a loss of performance, strange noises in the turbocharger, even detonation and cylinder misfires, depending on how much the turbocharger overheats the engine. Engine damage could occur, so this fault should be repaired as soon as possible.

How do you troubleshoot code P0039 ?

Because DTC P0039 describes a circuit problem, you’ll need a DMM (digital multimeter) and vehicle-specific EWD (electrical wiring diagram) to diagnose and repair it.

  • Fuse & Wire Harness Check – The easiest thing to check is the fuse, if applicable. Then check the wire harness between the ECM and the BCS. Check for obvious damage or chafing. Check for bent or broken pins, corrosion, or evidence of water entry. Repair as needed and be sure all connectors are seated properly.


  • BCS Check – Unplug the BCS and check for resistance across the terminals. Typical resistance should be between 10 Ω and 25 Ω, but check your repair manual to be sure. If there is an open circuit, ∞ Ω or OL on your DMM, or a short circuit, 0 Ω, replace the BCS.
  • Circuit Check – Unplug the ECM and BCS. Check for continuity from end to end on each pin and check for short circuits between pins and to ground. There should be no resistance from the ECM to the BCS, and there should be infinite resistance, over 10 kΩ, to ground. Repair as necessary.


Codes Related to P0039

  • P0033 Turbo/Super Charger Bypass Valve Control Circuit
  • P0034 Turbo/Super Charger Bypass Valve Control Circuit Low
  • P0035 Turbo/Super Charger Bypass Valve Control Circuit High
  • P0045 Turbo/Super Charger Boost Control Solenoid Circuit/Open
  • P0046 Turbo/Super Charger Boost Control Solenoid Circuit Range/Performance
  • P0047 Turbo/Super Charger Boost Control Solenoid Circuit Low
  • P0048 Turbo/Super Charger Boost Control Solenoid Circuit High