P2261 code definition
Turbo/Super Charger Bypass Valve - Mechanical
What the P2261 code means
The P2261 diagnostic trouble code is an indication that the turbo/super charger bypass valve mechanical control circuit is giving the Powertrain Control Module (PCM) a reading that is abnormal.
The purpose of the turbocharger is to force air into the engine in order to increase horsepower. This is accomplished when the turbocharger moves impellers that are located in two separate housing chambers.
The impeller in the first chamber turns as engine exhaust pressure is forced through it. The impeller in the first chamber then turns the impeller in the second chamber. The second chamber impeller picks up cooler air from intercoolers and the turbocharger intake system and forces dense air into the engine.
Fuel that is dense boosts increased horsepower, and the rise of revolutions per minute (RPM). Boost pressure is achieved with high RPMs, and the engine cannot operate properly if boost pressure is excessively high or low (boost pressure specifications are determined by the manufacturer and programmed into the PCM).
When the boost pressure is higher or lower than the predetermined specifications, the PCM will store the P2261 trouble code, and the Check Engine Light will come on.
What causes the P2261 code?
- Intake manifold vacuum leak
- Dirty air cleaner
- Wastegate that is stuck open
- Wastegate that is stuck closed
- Faulty intercooler
- Bolts between the turbocharger and exhaust manifold that are loose
- Faulty boost sensor
- Boost sensor wiring that is shorted or open
- Boost sensor reference circuit connectors that are loose, disconnected, or corroded
- Turbo failure caused by internal oil leaks and/or oil supply restrictions
What are the symptoms of the P2261 code?
- Difficulty with acceleration
- Rattling sound coming from the turbocharger and/or turbo pipes
- Smoke coming from the exhaust
- High engine temperatures
- High transmission temperatures
- Hissing sound coming from the turbocharger wastegate and/or turbocharger hoses
- Loss of engine performance
- Unusual boost pressure levels
- Fouled spark plug
- Cylinder combustion
- Other diagnostic trouble codes stored along with P2261, such as boost codes, engine misfire codes, or knock sensor codes
How does a mechanic diagnose the P2261 code?
Inspects wiring and connectors for shorts, burns, and corrosion
Clears the codes and runs the engine (if the P2261 code does not come back, it is an indication that an intermittent problem exists, which cannot always be diagnosed immediately)
Makes sure there are no misfire conditions
Makes sure that the turbo hose clamps are tight
Makes sure that the turbo intake hoses and intercooler hoses are free from leaks and cracks
Makes sure that the air intake hoses are tight and not damaged in any way.
Makes sure that the vacuum lines are not cracked, torn, or disconnected.
While running the engine, gets the RPMs up to 5,000 and releases the throttle (uses a boost gauge to observe boost pressure levels)
If boost pressure levels are above 19 lbs., this is an indication that the westgate is faulty.
If boost pressure levels fall below 14 lbs., this is an indication that there is a problem with the turbocharger or exhaust.
- Uses a vacuum pump to see if the wastegate is functioning properly
If an extreme drop in boost pressure is observed, this is an indication that the wastegate is not closing completely.
If low boost pressure is observed, this is an indication that the wastegate is not opening completely.
Inspects the inside of the turbo outlet hose for standing oil
Inspects the impeller for damage and whether the impeller is making contact with the inner housing and checks to make sure that there are no loose bearings (if any of these conditions exist, it is an indication that the turbocharger is defective)
Checks the voltage and resistance of the turbocharger boost sensor electrical circuitry and connectors (if the voltage and resistance readings do not coincide with the specifications that have been predetermined by the manufacturer, the circuitry will need to be replaced or repaired, as necessary)
Common mistakes when diagnosing the P2261 code
One common mistake when diagnosing the P2261 trouble code is not inspecting the turbocharger oil system to determine whether it is necessary to clear debris and/or obstructions.
Another mistake that is commonly made is replacing the turbocharger before making sure the wastegate and circuitry is operating properly.
How serious is the P2261 code?
The symptoms of the P2261 diagnostic trouble code will affect the overall engine performance of the vehicle. Some of these symptoms include:
- a lack of power
- poor acceleration
- spark plugs fouling out
These symptoms will make the vehicle difficult to operate. For this reason, the P2261 trouble code is considered a serious one and should be diagnosed and repaired as soon as possible.
What repairs can fix the P2261 code?
- Replacing damaged vacuum line
- Replacing intake manifold gasket
- Replacing air filter
- Replacing wastegate
- Replacing intercooler
- Replacing or tightening bolts between the turbocharger and exhaust manifold
- Replacing boost sensor
- Repairing or replacing boost sensor wiring
- Repairing or replacing boost sensor reference circuit connectors
- Replacing turbo or oil lines leading to the turbo that are restricted
Additional comments for consideration regarding the P2261 code
There are a lot of components in the turbo system that help control turbo boost. It is important to check all of the turbo system components while diagnosing this trouble code. It is also important to mindful that loose or broken vacuum hoses have the potential to cause the P2261 diagnostic trouble code to be stored by the Powertrain Control Module (PCM).
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