HOW TO DISABLE EWS ON E36 BMWs
Updated: Jul 20
If you have been around BMWs long enough, I am sure you will hear the term EWS or some people say EWIS. This term will become more prevalent to you if you are swapping an E36 engine into another E36 or a different chassis. EWS is also on other models like E34, and other engines like M60, but for the sake of this article, we are only going to be talking about the E36.
So what is EWS? EWS stands for “Elektronische Wegfahr Sperre.” Good now that you know what it means we can move on…I am just kidding, I won’t leave you hanging there. This is German for Electronic Immobilizer, or BMWs electronic protection system.
The reason I am writing this article is because I ran into a new issue last week with our S50 swap into our 1996 E36 touring project. Before this week, I thought EWS was only on OBD2 cars (1996.5+), but our engine was a S50, and our car is the early 1996 version, making it OBD1.
When trying to crank the car for the first time, nothing happened. We immediately started going down the list and testing for air, fuel, and spark. We knew we had air, so we moved on to fuel. We disconnected the fuel line at the front of the fuel rail and fuel came out, check two. Next was spark. We removed one spark plug and while keeping it attached to the coil pack, grounded it out on the nearest bolt and cranked the engine. Nothing, no spark. So why weren’t we getting the main relay to turn on to tell the coil packs to fire?
We found out that the EWS systems on the E36 platforms varied throughout the years (EWSI, EWSII). There was no one system. EWS has also been known to fail, so this isn’t just an engine swap problem. EWS module failures, antenna failures, and ignition failures with your key can all happen.
So if you have a starting problem, what can you do? Well since the EWS system has been known to cause issues, the easiest way is to just delete the system.
On OBD2 cars (MS41 DME), you will need to have it sent off to a tuner, so they can flash the ECU. This will remove any EWS bits, and make the computer be able to talk with the ignition. After this is done, you will not have any problems and you will be good to go.
On OBD1 cars, (413/506 DME), you will need to replace the chip inside. These chips can usually be purchased by the same tuners, or on other BMW websites out there. Unfortunately on OBD1 cars, replacing the chip is only half the battle and this is where we became frustrated.
If your OBD1 E36 was equipped with the EWSI, you will also need to remove the link between the EWS computer and the DME. This will require a little bit of wiring knowledge. There are two ways to accomplish this:
Disconnect pin 66 on the DME side
Disconnect or cut pin 7 (green wire) on the X20 plug side.
We would recommend performing the latter of the two, and disconnecting on the X20 plug side. The easiest way is to just cut the #7 green wire, but if you want to do it properly and completely remove the pin, it takes a little more effort.
The x20 plug can be unplugged by simply twisting the cap counterclockwise. We will be working with the top part of the plug or the female side. Inside the x20 plug, there is a middle ring. This is the locking mechanism for the plug. You will need to twist this counterclockwise to unlock it. It will click once. You may want to try using needle-nose pliers or a pair of snap ring pliers. Once you hear the click you can take a small screwdriver and push pin #7 out through the connector. Once the pin is removed, turn the inner lock clockwise to lock the pins in again. Make sure to verify that the connector is locked and no other pins can come out. After this, connect the X20 plug again and you are good to go. Once this is accomplished your car should receive spark and be able to start right up…unless you have EWSII.
With EWSII E36s, there is also a starter lockout that must be disconnected. You will need to find the EWS module in the glovebox. You will need to physically remove the glovebox to get back to the electronics behind it. On the EWSII module, there are 2 large or thick wires, which are for the starter solenoid. You can either cut these two wires and use a butt connector to tie them in, or you can take another piece of wire and loop those two terminals together to connect the circuit. After this, your car will startup.
Hopefully, this helps anyone with no start conditions on their cars.
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