What the P2640 code means
The P2640 code tells you that a malfunction in the torque management feedback signal has occurred in the PCM or in one of the other control modules. These control modules may include the body control module, the traction control module, the transmission control module, the fuel injection control module, the instrument panel control module, the anti-theft module, the turbo control module, the cruise control module, proximity alert module, the climate control module, and the antilock brake control module.
What causes the P2640 code?
There may be one or more causes for the P2640 code. One is a defective driver in the PCM. You may also have a poor electrical connection, shorted or corroded wiring in the CAN Bus harness, a broken ground wire, or, in a worst scenario, your CAN bus may be defective.
What are the symptoms of the P2640 code?
Symptoms for the P2640 code include difficulty shifting, a decrease in fuel economy, a stalling engine, a stored trouble code, poor acceleration, and an illuminated service engine light.
How does a mechanic diagnose the P2640 code?
An OBD-II scanner and a digital volt/ohm meter will help you perform a successful diagnosis. Too often symptoms and stored codes that appear as a reaction to a failure in communication are misdiagnosed, which leads to an unsuccessful repair. Engine misfire codes, fuel injector codes, lean exhaust codes, and almost any other drivability or transmission code that is accompanied by a controller communication code can lead to a misdiagnosis. Remember always to diagnose codes in the order in which they appear. You can use freeze frame data to help you determine the order in which the codes appeared. Freeze frame data simply stores the operating conditions of the engine as soon as those conditions occur. It is very important that you know the order in which the codes appeared, as well as the conditions under which they were set; freeze frame data will provide this information.
Common mistakes when diagnosing the P2640 code
Always begin by inspecting the wiring and connectors. To do this, use an OBD-II scanner and a digital volt/ohm meter. After inspection, replace or repair any shorted, damaged, disconnected, or corroded wiring, and connectors. Remember to record all codes and freeze frame data. Afterward, clear the code and then test-drive the car to see if the code reappears. If the code does not reappear immediately, you may have an intermittent condition, which is harder to diagnose. Unlike most diagnostic codes, an intermittent condition code is often better left to a professional due to added difficulty in diagnosing it. Also, an experienced professional may have a specialized scanner, such as a Tech II or an Autohex, which will help them determine the area of the malfunction more easily and efficiently.
How serious is the P2640 code?
The P2640 code is serious and, unless you are very skilled and have the proper tools, should be looked at by a professional technician.
What repairs can fix the P2640 code?
To diagnose this type of code using a digital volt ohmmeter would require that you probe thousands of circuits, one at a time. Obviously this is time-consuming and may not yield the results you want. And remember that if one probe is misplaced, you can destroy costly control modules thereby causing your vehicle to be completely reprogrammed. Continuity tests, which you perform after all modules have been disconnected, can take 40 hours or more to complete. However, if you do decide to take this on yourself and not consult a professional, make sure that you start with a thorough visual inspection of your car’s circuitry, fuses, and connectors. Watch out for corroded or loose electrical connectors that could cause the P2640 and other codes like it to be stored.
Additional comments for consideration regarding the P2640 code
Many older vehicles have temporary sensor problems that occur due to prolonged stress on the drivetrain. A P2640 can be very difficult to diagnose and repair, and your best bet may be to get your car into a technician who has the tools to diagnose your problem more accurately and in less time. But if you do decide to do this yourself, make sure that you read up on the different ways to repair the issue, and always take note of your freeze frame data – this will provide you with valuable information.
Need help with a P2640 code?
YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online at https://www.yourmechanic.com or speak to a service advisor at 1-800-701-6230.