TDS Chips for BMW M51 and M41 engines

This guide will show you how to order and fit an eTune TDS chip into your ECU. EndTuning is able to supply various chips for the popular M51 and M41 diesel engines. The M51 was a hugely sucessful engine used by many other manufacturers and has been known to appear in kit cars and engine conversions.
Ordering and fitting a chip can be done without any major technical skills, but we are here to help you if needed. There are a huge number of different ECUs and software versions covering the TDS engine range, so feel free to contact us if assistance is required. To identify your ECU and desired chip, we'll need to know two things. Firstly, the Bosch ECU part number which will be printed on the front of the ECU case. Look for a prominant code starting with 0281 XXX XXX. This will identify the hardware, the basic computer that runs the engine.
The second important piece of information to identify the required chip is the software code. This will be a 3 digit code also on the front. This code will usually be in a Number/Letter/Number format. For example, 3G2, 5E1, 3Y4 etc. It is often found on a white sticker, in the top right corner.
These numbers will identify the original software version used by the ECU, which will allow me to select the right chip for you. In the majority of cases, I will have the data ready to create a custom chip for you, but occasionally there may be a rare version which I have not yet seen. In those cases, I may need to work on the ECU directly. The chips are priced at £75 including UK postage, but other destinations can also be covered. Power and torque are considerably increased, with conservative estimates of 170bhp/350Nm on an intercooled 2.5 TDS, and 120bhp/240Nm on the M41 318TDS. Furthermore, these engines can produce even more power with a cat deletion ("decat") pipe and EGR blanking, with reports of over 180bhp. To order a chip, fill in the webform at the bottom of the page with the ECU number and Software variant code. Orders are usually processed the same day for fast delivery.

Installation Instructions

Firstly you'll need to remove the ECU from the vehicle and get it to an area to work on it. The top case is made of thin pressed metal, and has 11 tabs around the edges. Bend these back with the tip of a screwdriver to release and remove the lid.

Above you can see a typical TDS ecu showing the ECU hardware and software numbers on the case lid, the tabs that need to be released, and 4 large Torx screws that will need to be removed.
Shown below are another 4 smaller Torx screws that surround the connector socket.

The main circuit board can now be removed from the heavier cast bottom section of the ECU, and this contains the chips we will be working on. There are 3 push fit clips that pass through both levels and hold them in position. Pulling on the top will release them.

A further two clips at each side of the grey ribbon connector will also need to be disconnected. I find gently prising open the "leaves" of the connectors reduces the grip to easily detatch the top and bottom half.

Fitting the Chip

You will now be able to open up each half of the ECU to gain access to the chips inside. There may be as many as 3 chips in some models, and don't be worried if your ECU looks different to the one pictured below. The chips will be under plastic clips to hold them secure. Flick these off with a sharp screwdriver and you should be faced with something looking like our picture. On some models of ECU, I might need you to tell me the numbers on the silver stickers you can see on each chip. Only one chip will be changed, remember to match the numbers up when swapping.
Lever up the existing chip gently on each of the short edges, so the chip comes up as straight as possible. You can now push the new chip into the same socket. All chips and sockets have a small notch or cutout on one side. Match up the notch in the chip over the notch in the socket and push the chip home firmly. You can now refit the clip and reassemble the ECU. Refit into your vehicle and you are ready to go!

Ready to order?

Simply fill out the webform below with your ECU Hardware number and Software variant and click the "Buy It Now!" button. Payments can be made with either a Paypal account or through a Credit or Debit card.

Bosch Hardware Number
Software Variant