BMW E28 5-Series M30 Engine + EH Transmission Throttle Position Sensor Removal and Re-Installation

If you like, you can skip directly to where you can buy this part.

Although the throttle position sensor is important, my impression is that it won’t make a difference as to the engine totally failing to start or run.

The throttle cable end that is attached atop the motor rotates a shaft. Its position is sensed by the throttle position sensor. Following this logic should make it easier to locate the throttle position sensor.

The throttle position sensor is different for mid-1980s BMW cars with the ZF 4 HP-22 EH transmission. This is why it’s such a rare part.

The following pictures show the dust cover that covers the throttle position sensor.



A vacuum hose runs on top of the dust cover. That hose is in the way, so I removed it by gently pulling it off.

IMAG8486That made the dust cover nicely accessible.

IMAG8487I pulled on the two tabs on the dust cover. It’s flexible, so this enabled me to move the dust cover away from the throttle position sensor.

IMAG8488This exposed the throttle position sensor.

IMAG8489I removed the driver side long screw that attaches the backing plate to the throttle body. When I pulled the screw out, some spacers came loose. They tend to fall, so you might want to be ready for that.

IMAG8490I could not reach the passenger side screw without first removing the strut onto which the diagnostic plug is mounted. The strut came loose after removing a 13mm bolt and a 13mm nut.

IMAG8499Before I could remove the strut, I pried off the diagnostic plug cap, and then I used a flat-tip screwdriver to remove the clip that attaches the diagnostic plug to the strut. This enabled me to remove the strut while leaving the plug in place, attached to its nicely flexible wiring.

Here is a picture of the strut, cap and clip, removed from the car.

IMAG8502This enabled me to reach the passenger side screw that attaches the base plate to the throttle body. I removed it, and needed to be ready to  catch the falling spacer.

IMAG8498Next, I moved the round three-wire plug away from its mount.

IMAG8492The plug is made of soft, pliable rubber or plastic. I needed to deform and bend it a little to loosen the plug. It seemed quite robust and wasn’t damaged in the process.

IMAG8493 IMAG8494 IMAG8495 IMAG8496Next, I removed the two individual wires that go to the switch. One is blue-ish, one is brown-ish. Due to aged wiring (the car’s not mine) it’s hard to tell.

IMAG8500This enabled me to lift away the base plate, with the two throttle position sensor components attached to it.

IMAG8505The mechanism relies on a black plastic spindle that’s mounted on the eccentric axle that runs through the throttle body.  It’s a friction fit. To remove it, gently pry it away from the throttle body and slide it off the axle.

IMAG8503This frees up the base plate, too.

IMAG8504Re-installation is the reverse of removal, though you might need to tweak the position of the new throttle position sensor so that it correctly senses when you’re at idle, and when you’re at “wide open throttle.”

You can hook an ohmmeter to the parts (and NOT to the wiring) to check the values, to see when the parts register the relevant throttle positions.

You don’t need an assistant to step on the throttle pedal because you can simulate the throttle pedal action by yanking on the accelerator cable, the end that’s on top of the valve cover.

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