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Motor Age Garage: Automotive IV

Sunday, July 1, 2018 - 06:00
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I was recently called to a shop on a 2012 BMW X5 with a 3.0 Liter Engine (Figure 1) that needed a new Engine Control Module (ECM) programmed. The shop had determined that the ECM was internally damaged and needed to be replaced. They purchased a new ECM from the dealer because a used one would not work on this vehicle due to the fact that BMW will not allow it. Most manufacturers have a procedure to overwrite the Vehicle Identification number and realign the module with the onboard Vehicle Security System but that is not the case with BMW. Their Engine Control Modules are a “One-Time” marriage and it is required to purchase a new ECM from the dealer only.

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Figure 1

When I arrived at the shop, I needed to see for myself how the shop came to the conclusion that the ECM was damaged. This can usually be determined by a visual inspection or by a simple “smell” test for any signs of a burnt circuit board. Just going on an assumption can be VERY costly if you are wrong in your diagnostic process so I needed to make sure the shop was headed in the right direction. It would be a bad situation if I was hired to program a control module and the vehicle ended up with the same results as the old one. I was hired as a salesman to stuff software and a configuration file into the ECM, and though I wear many hats, my “technician” hat was not the one I was wearing today. However, I could always be hired later to diagnose the vehicle if needed. So I did as I was told and kept my fingers crossed.

This is new!
The head technician in the shop did assure me of his findings by letting me see for myself what he had found prior to me starting the programming procedure. He pointed out a pile of damaged components (Figure 2). I was taken back by his findings and the amount of damage involved on this vehicle. This vehicle uses an electric water pump that had failed. It had basically burnt up and took out components in its path of destruction. By taking a closer view of the water pump (Figure 3) you could see the damage the water pump caused to the water pump connector.

Figure 2
Figure 3

The shop simply replaced the water pump and wired a new connector end to the existing harness but the vehicle did not run very well and was setting a few running codes for Injectors and ignition coils. When the technician did further diagnostics he discovered a burnt connector at the ECM (Figure 4) and he had no other choice but to replace the ECM along with a sub harness for the ECM. What a chain reaction of events for a simple water pump replacement job after the owner of the BMW drove the car to the shop complaining about a CEL lamp on, burning smell from the engine compartment and a vehicle that was not running well.

Figure 4
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