The EWS (Elektronische Wegfahr Sperre), or Electronic Immobilizer, is a common source of frustration for BMW E36 owners, especially during engine swaps or when encountering no-start conditions. This guide provides a detailed walkthrough of the E36 Ews Delete process for both OBD1 and OBD2 systems.
Understanding the EWS System and its Variations
The EWS prevents unauthorized engine starting by communicating with the DME (Digital Motor Electronics) and immobilizing the starter or ignition. E36 models utilize two main EWS versions: EWSI and EWSII. While often associated with OBD2 cars (1996.5 and later), EWSI can also be found in early 1996 OBD1 models. This can be a surprise for those undertaking engine swaps, as it was for us during an S50 swap into a 1996 E36 Touring.
Troubleshooting EWS Related No-Start Issues
A malfunctioning EWS can manifest as a complete lack of spark or starter engagement. Before undertaking an EWS delete, ensure you’ve exhausted other potential causes, such as:
- Fuel Delivery: Verify fuel pressure and injector pulse.
- Spark: Test for spark at the spark plugs.
- EWS Components: Inspect the EWS module, antenna ring around the ignition key cylinder, and the key itself for damage or failure.
Performing an E36 EWS Delete: OBD1 vs. OBD2
The EWS delete process differs significantly between OBD1 and OBD2 E36s.
OBD2 (MS41 DME) EWS Delete
OBD2 E36s require ECU reflashing by a professional tuner. This process removes the EWS software from the DME, allowing the engine to start without EWS authentication. This is a relatively straightforward process once the ECU is sent to a tuner experienced in BMW software.
OBD1 (413/506 DME) EWS Delete
OBD1 cars require a replacement DME chip programmed to bypass the EWS. However, this is only part of the solution. Depending on the specific EWS version, further steps may be required.
EWSI Delete: Disabling DME Communication
With EWSI, you need to sever the communication link between the EWS module and the DME. This can be accomplished by:
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Disconnecting Pin 66 on the DME: This method requires accessing the DME wiring harness.
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Disconnecting/Cutting Pin 7 (Green Wire) on the X20 Connector: This is the recommended method. Locate the X20 connector, unlock the inner retaining ring, and carefully remove or cut the green wire at pin 7.
EWSII Delete: Bypassing the Starter Lockout
EWSII systems incorporate a starter lockout relay controlled by the EWS module. To bypass this, locate the EWS module in the glove box area. Identify the two thick wires connected to the starter solenoid circuit on the EWS module. Connect these two wires together using a butt connector or a jumper wire.
After completing these steps, your E36 should start without EWS interference. Always double-check your wiring and ensure all connections are secure before attempting to start the engine.
