BMW 850Ci Powertrain Control Module Replacement Cost

Know what price you should pay to get your vehicle fixed.

The average cost for a BMW 850Ci powertrain control module replacement is between $1,207 and $1,219. Labor costs are estimated between $44 and $56 while parts are priced at $1163. Estimate does not include taxes and fees.
Note about price: The cost of this service or repair can vary by location, your vehicle's make and model, and even your engine type. Related repairs may also be needed. Talk with a RepairPal Certified shop to learn which repairs might be right for you.

How do Powertrain Control Modules work?

Battery power is supplied to the PCM, and the PCM is programmed to send that electricity at regulated voltage to engine sensors, other control units, other devices on the network, and every system in the vehicle that depends on information from the PCM to function properly. Information is simultaneously passed back into the PCM from all of these locations, allowing the PCM to monitor conditions, and be monitored for conditions at all times. Since many systems are being integrated at all times, the control modules of the vehicle will communicate via a common area communication (CAN-BUS) network. This allows for faster communication, less wires, and increased opportunity for advances in vehicle function.

What are the symptoms of a bad Powertrain Control Module?

When the PCM fails, being one of the more important computers on the vehicle, the PCM may make erroneous calculations, fail to connect, fail to operate, or fail to interpret data correctly. This leads to constant malfunctions in most systems in the vehicle because systems dependant on PCM data have improper signals from the PCM. This will trigger the check engine light, and the possibilities of on-board diagnostic (OBD) trouble codes stored are endless. However, in many situations, a computerized scanning tool, or a handheld scanner will fail to connect to the vehicle. The symptoms of the vehicle depend on the impacted systems, and the worst case scenario is a vehicle that does not start or stay running.

Can I drive with a bad Powertrain Control Module?

In most situations, driving a vehicle with a failed PCM is impossible as the systems needed to run the vehicle are not being instructed any longer. The PCM is a vital computer, and with this component sending erroneous signals, the vehicle will most likely never start, or the engine will randomly shut off. If a vehicle is responding very strangely to driver inputs, the vehicle should be towed to a repair facility.

How often do Powertrain Control Modules need replacement?

The engine control module, or powertrain control module, is known to fail frequently in small groups of vehicles, however, failure in most vehicles is not extremely common. Most vehicles will be crushed with the original PCM in place. That is not to say it cannot happen, in fact, as early as 75,000 miles, up to 125,000 miles is the most common range for PCM replacement for several popular vehicles.

How are Powertrain Control Modules replaced?

Replacing the PCM is normally easy since diagnostics will require the PCM be accessed for diagnostic testing prior to replacement. The technician may need component location reference material to find where the manufacturer installed the PCM. In most vehicles, the PCM is in the engine bay, but a few manufacturers place the PCM inside the vehicle. In some vehicles, the PCM is even located in the trunk. Once the PCM has been located, any obstructions to testing and replacement must be removed, and testing begins. If the PCM fails diagnostic testing, the PCM will be unplugged, replaced, and reconnected to the vehicle prior to final assembly and testing.

RepairPal Recommendations for Powertrain Control Module issues

Electrical diagnostics in general can be problematic, and there are many variables to account for. When electrical problems arise, diagnostics may take several hours to complete, or just a few minutes. This will significantly impact the cost of repairs. Choosing a facility with proper equipment and training for their staff may significantly reduce diagnostic time needed.

What to look out for when dealing with Powertrain Control Module issues

The battery connects directly to the engine, meaning it is grounded to the same point as many engine sensors. If the battery is incorrectly installed in a vehicle, such as installing or jump-starting the battery backwards, the PCM can be destroyed, along with some sensors and wiring. In many occasions, the PCM connector, harness, or pins inside the connector socket fail, and cannot make a proper connection to the PCM. Except for a broken or missing pin, these items can be replaced, and the vehicle retested.

Can I replace the Powertrain Control Module myself?

Replacing the PCM on most vehicles is fairly easy, but accessing the control module usually requires searching behind panels if the component cannot be identified through a vehicle repair database. In many cases, the PCM looks much like a few other computers that are mounted in the vehicle, and removing a few panels to find the wrong module will quickly become frustrating. If proper experience, and reference materials are available, the PCM can be replaced, but many will need to be calibrated by the manufacturer. If this process is understood, and the PCM is adapted to the vehicle, this is a money saver, however, if diagnostic procedures are not fully understood, this should be trusted to a professional.