Hall Sensor Wiring and Repair

[NC944er]

I spent some time sorting through the Hall Sensor wiring on a 944S and found a lack of details on the circuit, so I figured I’d share some findings.

Because of the sensor’s location near the exhaust manifold, the plastic connectors tend to become brittle and fall apart over time. This particular car had lost both connectors for the sensor and the wiring harness side, and a prior “repair” was done with some crimp-on spade terminals.

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After referencing the factory workshop manual, the breakdown is as follows:

• Pin 1 on the Hall Sensor has a Red wire > connects to Pin 31 on the DME Computer (positive voltage from computer to sensor)

• Pin 2 on the Hall Sensor has a Green wire > connects to Pin 8 on the DME Computer (signal from sensor to computer)

• Pin 3 on the Hall Sensor has a Black wire > connects to the Shield Wire on the harness (ground connection)

• The manual indicates that Pin 31 should have a Black wire on the harness side and that Pin 8 should have a Yellow wire on the harness.

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For whatever reason, the harness for this car had White and Brown wires, not Black and Yellow. After testing continuity between the wires and Pins 31 and 8 on the DME connector, it turns out that the White wire goes to Pin 31 and the Brown wire goes to Pin 8.

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When installing the JPT terminals, the leading section of the shield cable has to be twisted into a smaller wire (shown as a black wire below, covered in heat shrink).

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Everything is now routed correctly.

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Here’s a view of the new Hall Sensor installed and the wiring harness repaired.

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[Sansho]

I got my hall sensor repair parts from Ballenger Motorsports at https://www.bmotorsports.com/. (No affiliation, etc).

[Latitude48]

I got my hall sensor repair parts from Ballenger Motorsports at https://www.bmotorsports.com/. (No affiliation, etc).

FWIW I purchased a new Bosch Hall Sensor from FCP Euro for my 944 S2. It looks like the OP's repair also included a new cam belt cover set. I have a new set I want to install on my S2 too.

[chrischrischris]

It took me a few minutes to understand that the black wire IS the metal shielding twisted into a wire and covered in heat shrink.

I need to do a similar repair but to the opposite side - the male connector attached to the sensor. I guess a "better" repair could be to replace the whole sensor assembly, but I'd rather not. Happy to see repair kits are available for that as well. What's the shielding situation with the sensor wire?

[NC944er]

It took me a few minutes to understand that the black wire IS the metal shielding twisted into a wire and covered in heat shrink.

Good call out! I’ve edited it for clarity, thanks!