U0140 Lost Communication With Body Control Module

OBD-II Trouble Code - U0140 - Data Sheet

Lost Communication With Body Control Module

What does DTC U0140 mean?

This is a generic powertrain code which means it applies to all makes / models from 1996, including but not limited to Ford, Chevrolet, Nissan, GMC, Buick, etc. However, specific troubleshooting steps may differ from vehicle to vehicle.

The Body Control Module (BCM) is an electronic module that is part of the vehicle's entire electrical system and controls functions including, but not limited to, tire pressure sensor, remote keyless entry, door locks, anti-theft alarm, heated mirrors, rear defroster windows, front and rear washers, wipers and horn.

It also receives shift signals from seat belts, ignition, horn telling you the door is ajar, parking brake, cruise control, engine oil level, cruise control, and a wiper and wiper. Battery discharge protection, temperature sensor, and hibernation function may be affected by a bad BCM, a loose connection to the BCM, or an open / short circuit in the BCM harness.

Code U0140 refers to the BCM or the wiring to the BCM from the Engine Control Module (ECM). The code, depending on the year, make and model of the vehicle, may indicate that the BCM is defective, that the BCM is not receiving or sending a signal, the BCM wiring harness is open or shorted, or that the BCM is not communicating. with the ECM via the controller network - CAN communication line.

Example of a body control module (BCM):

The code can be detected when the ECM has not received the emissions CAN signal from the BCM for at least two seconds. Note. This DTC is basically identical to U0141, U0142, U0143, U0144, and U0145.

Symptoms

Not only will the MIL (aka check engine light) come on, notifying you that the ECM has set a code, but you may also notice that some body control functions are not working properly. Depending on the type of problem - wiring, the BCM itself, or a short circuit - some or all of the systems that are controlled by the body control module may not work correctly or not work at all.

Other symptoms of engine code U0140 may include.

• Misfire at high speeds
• Shivers when you increase your speed
• Poor acceleration
• The car may not start
• You can blow fuses all the time.

Possible Causes of Error U0140

Several incidents can cause the BCM or its wiring to fail. If the BCM is electrocuted in an accident, that is, if it is shaken hard enough by the shock, it may be completely damaged, the wiring harness may be knocked off, or one or more of the wires in the harness may be exposed or cut completely. If a bare wire touches another wire or a metal part of the vehicle, it will cause a short circuit.

Excessive heating of a vehicle engine or fire can damage the BCM or melt insulation on the wiring harness. On the other hand, if the BCM turns out to be waterlogged, it will most likely fail. In addition, if the sensors are clogged with water or otherwise damaged, the BCM will not be able to do what you tell it to, that is, remotely open the door locks; it also cannot send this signal to the ECM.

Excessive vibration can cause BCM wear, such as from unbalanced tires or other damaged parts that can vibrate your vehicle. And simple wear and tear will eventually lead to the failure of the BCM.

Common reasons for this code include:

• Faulty Body Control Module (BCM)
• Body control module (BCM) circuit poor electrical connection
• Body Control Module (BCM) harness open or shorted

Diagnostic and repair procedures

Check the BCM service bulletins on your vehicle before attempting to diagnose the BCM. If the problem is known and covered by the warranty, you will save diagnostic time. Find the BCM on your vehicle using the appropriate workshop manual for your vehicle, as the BCM can be found in different locations on different models.

You can help determine if the problem is the BCM or its wiring by noting what is not working on the vehicle, such as door locks, remote start, and other things that the BCM controls. Of course, you should always check the fuses first - check the fuses and relays (if applicable) for non-working functions and for the BCM.

If you think the BCM or wiring is defective, the easiest way is to check the connections. Rotate the connector carefully to make sure it does not dangle. If not, remove the connector and make sure there is no corrosion on both sides of the connector. Make sure none of the individual pins are loose.

If the connector is okay, you need to check for the presence of power at each terminal. Use the body control module diagnostic code reader to determine which pin or pins are having a problem. If any of the terminals are not receiving power, the problem is most likely in the wiring harness. If power is applied to the terminals, then the problem is in the BCM itself.

U0140 engine code hints

Before replacing the BCM, consult your dealer or your favorite technician yourself. You may need to program it with advanced scanning tools available from your dealer or technician.

If the BCM connection looks burnt, check for a problem with the wiring or the BCM itself.

If the BCM smells like burning or some other unusual odor, the problem is most likely related to the BCM.

If the BCM is not receiving power, you may have to trace the harness to find an open in one or more wires. Make sure the wire harness is not melted.

Keep in mind that only part of the BCM can be bad; so your remote may work, but your power door locks won't - unless it's the part of the BCM that isn't working properly.

How serious is code U0140?

The level of severity associated with error code U0140 often depends on which part of your vehicle is at fault. This code can cause your car to shake when accelerating. Error code U0140 can also cause your car's anti-theft locks or key locks to fail. In general, this code should be taken very seriously.

Can I still drive with code U0140?

Drivers with DTC U0140 should have their vehicle scanned and repaired as soon as possible. Driving is not recommended if the code affects handling and causes misfiring. This puts other drivers as well as yourself at serious risk of injury. If a misfire occurs, driving for an extended period of time can cause the engine to overheat and eventually fail.

How difficult is it to check code U0140?

A professional mechanic should perform all repairs to ensure both the safety of your vehicle and expedited repairs.

A qualified mechanic will usually repair the U0140 by replacing your vehicle's BCM. Be aware that if the connections to your BCM are burned out, the mechanic will check for problems with the wiring to the BCM. If the wiring also smells burnt or has other strange smells, the problem is most likely caused by a faulty BCM.

Also, if your BCM is no longer receiving power, your mechanic will check for holes in the wiring as well as looking for damaged or melted wiring insulation.

Common Mistakes

The following are some of the most common mistakes a technician can make when diagnosing code U0140:

• Missing Body Control Module Test
• While trying to check all the wires from the BCM, the technician may accidentally disconnect a wire important to the operation of the vehicle.
• Didn't check all the fuses in the fuse box
• Not replacing a blown fuse with the correct number
• Neglect of checking the RPC for corrosion
• The scan tool for diagnosing all vehicle components is not connected.
• Do not check vehicle battery voltage and CCA
• Replacing parts that are not defective or incorrect

Related codes

Code U0140 is associated with and may be accompanied by the following codes:

C0040 , P0366, P0551, P0406 , P0014 , P0620 , P0341 , C0265, P0711, P0107 , P0230, P2509

U0140 error code symptoms cause & solution [master class] diy

Need more help with the U0140 code?

If you still need help with DTC U0140, post a question in the comments below this article.

NOTE. This information is provided for informational purposes only. It is not intended to be used as a repair recommendation and we are not responsible for any action you take on any vehicle. All information on this site is protected by copyright.