Fault code P2071 is called “Intake Manifold Tuning (IMT) Valve Stuck Closed (Bank 1)” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.
Technical description and explained code P2071
Stored code P2071 means that the powertrain control module (PCM) has detected that the inlet manifold adjustment valve (IMT) is stuck in the closed position. Bank 1 indicates that the malfunction has occurred in the engine group which contains cylinder number one.
Intake manifold adjustments are used to limit and control intake air as it enters the individual manifold channels. The IMT not only regulates the intake air volume, but also creates swirls.
These two factors contribute to a more efficient atomization of the fuel, for better combustion. Each intake manifold channel is fitted with a metal damper, somewhat similar to a throttle valve.
One rod runs from one end of the manifold (for each engine block) to the other and through the middle of each channel. The metal flaps are attached to the rod, which rotates slightly to open and close the flaps.
Most commonly, the IMT stem is driven by a signal coming from the PCM. The PCM sends the appropriate voltage signal, and the IMT stem opens and closes the channel valves to the desired degree.
The PCM monitors the actual valve position to determine if the system is functioning as desired.
If the PCM detects that the IMT valve is stuck in the closed position, code P2071 will be stored and the malfunction indicator lamp (MIL) will illuminate. It may take several ignition failure cycles for the MIL to illuminate.
Symptoms of vehicle malfunctions
The main signal that an error P2071 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.
It can also be warning signs such as:
- The “Check engine” control lamp on the control panel will illuminate (the code will be stored as a fault).
- There may be no symptoms other than the stored fault code.
- There may also be other related fault codes (e.g. poor or rich exhaust).
- Floating revolutions, and attempts to stall while idling.
- Reduced engine performance.
- Increased fuel consumption.
Fault code P2071 should be considered serious, because if you have it, you most likely will not be able to activate the cruise control function.
Factors that can cause this error code
The error code P2071 can mean that one or more of the following problems have occurred:
- Loose or jammed inlet manifold guides.
- Defective IMT actuator valve.
- Open or short circuit in control circuit.
- Broken electrical connector.
- Sometimes the cause is vacuum leakage.
- Faulty engine control module (PCM).
How to fix or reset OBD-2 code P2071
Some suggested steps for troubleshooting and fix the error code P2071:
- Read all stored data and error codes with an OBD-II scan tool. To find out when and under what circumstances fault P2071 appeared.
- Clear the error codes from the computer memory and test-drive the vehicle to find out if the fault appears again.
- Visually inspect the electrical wires and connectors.
- Check the IMT actuator valve (Bank 1).
- Test the inlet manifold guides.
- Listen carefully for a hissing sound of escaping air to rule out a vacuum leak.
- If no problems are found anywhere, check and replace the Powertrain Control Module (PCM) if necessary.
Diagnose and repair of problems
The first thing to do when you find fault P2071 is to clear all the codes to see if it reappears. If it does not appear, perform test drives on the vehicle. To make sure that the code is active again after several operating cycles. If it activates again, continue with the diagnostics.
Next, you’ll need to locate the intake manifold control valve. This can be tricky because more often than not, they are installed inside, in the intake manifold.
That said, the connector for the valve should be fairly accessible, so inspect it. Look for broken contacts, melted plastic, etc. To make sure it makes a proper electrical connection.
Check the control valve
Using the capabilities of your OBD2 scanner, try to operate the valve and determine if it is working throughout the range. If you hear clicks coming from the intake manifold, they are most likely related to the operation of the intake manifold control valve.
If there is an abnormal clicking noise from the air intake while adjusting the sensor with the scanner. There is a good chance that there is an obstruction or the valve itself is stuck for one reason or another.
Therefore, you need to remove the valve and physically inspect it and the inside of the intake manifold for any obstructions. If there are no obstructions and clicks are present, you can try replacing the valve, that is most likely the problem.
Electrical check
Inspect the wiring harness associated with the control valve. These harnesses can go through engine parts and other high temperature areas. Also, over time, fraying or cracking can occur due to engine vibration.
If no problems are found, but fault code P2071 remains, look at the engine control module (PCM). It rarely fails, but it does happen.
On which vehicles does this problem occur most frequently
Fault code P2071 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:
- Audi
- Land Rover (Freelander, Range Rover)
- Mercedes-Benz (Sprinter)
Fault code P2071 can sometimes be found with other errors. The most common are the following: P065E, P0660, P0661, P0662, P2070.
