BMW Coil Socket Housing Replacement – 2 hours
A BMW coil socket housing replacement may be necessary if they have been changed to a newer part number.
We are not gamblers here at the Repair Guide (some of us gave up betting college football years ago), but we are willing to wager a pretty penny that you are reading this article because you just started a tune up and realized your new coils don’t fit. Hmmm…well according to your supplier they should fit. But you can’t seem to slip the socket housing onto the coil. Insert your expletives here.
Well don’t feel bad. We recently encountered the same situation on our 2006 530xi touring wagon during its first tune up since purchased in July 2019. A quick analysis of the issue on RealOem.com revealed the problem. In 2016 BMW discontinued a coil socket housing that affected just about every model produced between 2000 and 2016 (part number 12521437985). The discontinued socket housing does not fit newer coils and must be switched out with the updated version (part number 12527519996) when the vehicle is brought in for a tune up.
There may be other reasons requiring a BMW coil socket housing repair, including fixing broken cable harnesses or replacing their worn parts. These reasons, although possible, are unlikely since most mechanics will just install a new cable harness which already includes the updated socket housings.
Whatever the reason is for replacing your socket housings, it is important to remember that this repair requires disconnecting your battery before starting. DO NOT attempt any repair on your vehicle’s ignition system without removing the negative terminal from the battery…you can destroy sensitive electronics and cause catastrophic damage.
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This article assumes that the reader is updating or replacing their ignition coil sockets with the newer style as discussed above. Please check your vehicle on RealOem.com to verify this coil socket fits your vehicle before purchasing.
|Socket housing ignition coil – 19996||varies||12527519996||Genuine BME – replaces socket housing 12521437985|
Tools and Supplies
Screwdriver – micro set
Section 1 – Preparing for a BMW coil socket housing replacement
This repair applies to just about every model BMW produced with “pencil” style ignition coils, so it is not feasible for us to illustrate every application. Preparing for the repair usually requires removing the cabin filter assembly, moving cable and wiring harnesses and removing engine covers to expose the vehicles ignition coils. For more information on accessing your vehicles ignition coils, please refer to other articles on our site or reference a quality BMW repair manual like Bentley Publishers.
Section 2 – Replacing the ignition coil socket housings
- Before starting a BMW coil socket housing replacement, remove the negative terminal from the battery. Never attempt any work on your engine’s ignition system without removing the negative terminal to the battery first…you can cause catastrophic damage to sensitive electronic parts.
- Start by removing the coil packs on your vehicle by releasing the socket housings from the coils, and “pulling” the coils from the spark plug tubes. A socket extension works great if the coils are stuck.
- There are special tools on the market for removing and installing electrical connectors in socket housings, but using just a 3/64″ (1.5mm) and 5/64″ (2mm) flat blade screwdriver will get the job done.
- Start by inserting a 3/64″ screwdriver into the side of an old ignition coil socket housing and releasing the triangular plastic retaining clip that secures the ignition wires.
- Insert the 3/64″ flat blade screwdriver into one of the connections and push it out of the back of the socket housing. This is not always that easy…sometimes you may need to use the palm of your hand on the screwdriver to get the connector to release. Use patience. Continue pushing until the connector pops out of the back of the housing.
- Check to see if the connector was bent when removed from the old socket housing. Usually they just pop out and everything is fine…but if you had to use a lot of force to remove it (or if you had to manipulate it to get it out) plug it into the back of a coil to see how it fits on the metal leads. If it is loose or does not slide on the lead correctly, use your screwdrivers and/or a pair of needle nose pliers to make small adjustments until it fits correctly.
- We like to immediately install the connector we just removed into the new socket housing. This helps avoid mixing up the wiring order. Make sure the triangular plastic retaining clip on the new socket housing is released before installing the connectors.
- Push the connector into the new socket housing as far as you can with your fingers. Use a 5/64″ (2mm) flat blade screwdriver to “push” the connector from the back of the socket housing. Try and keep the blade of the screwdriver on the rubber insulation while pushing to avoid puncturing the wires. Keep pushing the connector into the new socket housing until it is in its proper position (see images below).
- When all three connectors have been properly installed in the new socket housing, lock the triangular retaining clip back in place.
- Repeat for the remaining coils. Replace the coils in the spark plug tubes and start the vehicle to make sure there are no misfires. If there is a misfire (or engine is running rough), check all of you connections to make sure they are tight. If engine is still running rough, you will have to hook up an diagnostic scanner to check which cylinder(s) is causing the issue. Pull the socket housing off the misfiring cylinder and confirm you have all of the connector leads in their proper position and there are no broken wires.
BMW Coil Socket Housing Replacement Finished
If you have any questions or comments, please feel free to contact us. And congratulations for Doing It Yourself!
This article applies to all applicable BMW models.