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Replacing the crank reference sensor

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Old 12-05-2015, 05:28 PM
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John McM
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Default Replacing the crank reference sensor

I'm completing a light refurb on my C4. One of the items I found in my engine drop is a heat affected crank ref sensor plug, where the sensor side literally crumbled. Rather than rebuild the plugs (part of the plug is fused in the receptacle) I ordered all new parts.

The newer sensor is a 996 part with a different plug, so the harness connector side must be changed as well.

Parts needed are:

996-606-105-00 [sensor]
999-652-916-49 [plug]
999-652-871-22 [connector]
999-704-161-40 [grommet]
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Old 12-05-2015, 05:29 PM
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John McM
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This bulletin was put out by Porsche. And the Wiring manual agrees with the colour
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Old 12-05-2015, 05:31 PM
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John McM
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The plug has numbers on it. So 1 is White, 2 is Brown and 3 is shielding. Seems pretty simple (if Pelican had sent me the right connectors grrr)
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Old 12-05-2015, 05:34 PM
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John McM
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However the wires on my old sensor appear to be White and Black not White and Brown. I assume that's just a manufacturing change, or is it? I get the body back this week and can look at the Harness then. In the meantime has anyone done this and found a similar colour difference?
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Old 12-05-2015, 05:35 PM
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John McM
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Btw the new sensor is a direct fit and as it's the same length as the old one I haven't adjusted the gap.
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Old 12-05-2015, 06:41 PM
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Vandit
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Why wouldn't you backdate the plug on the sensor side rather than messing with the car's harness? Are the 964-era OE style connector parts still available?
Old 12-05-2015, 06:55 PM
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C4inLA
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Are shims used to set gap?
Old 12-05-2015, 08:31 PM
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John McM
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Originally Posted by C4inLA
Are shims used to set gap?
The gap should be 1mm +\- 0.2mm. I image a feeler gauge would work although access is not easy even with the engine out of the car as the transmission case is close to it.
Old 12-05-2015, 08:33 PM
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John McM
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Originally Posted by Vandit
Why wouldn't you backdate the plug on the sensor side rather than messing with the car's harness? Are the 964-era OE style connector parts still available?
I believe they are AMP connectors and parts are available. As the male plug fused inside the female plug I needed to do two and even then I'm not sure why it fused in the first place. I thought it was best to start clean because replacing the sensor is easy when the engine is out.
Old 03-19-2016, 04:19 PM
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klokwerk
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Hi John,
How did this end up?

was the color coding correct for your installation?

Here is the harness connector I'm going to cut out to replace with the new oval connector.
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New parts:
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Since I'm doing this very same thing today and wanted to know how it turned out.

Thanks!
Old 03-19-2016, 04:37 PM
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John McM
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It worked fine. Car idles and revs correctly so it's getting the right signal to the ECU.
Old 03-19-2016, 05:22 PM
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klokwerk
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Did you tin the wires or solder them at all?

Thanks again!
Old 03-19-2016, 09:16 PM
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John McM
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Originally Posted by klokwerk
Did you tin the wires or solder them at all? Thanks again!
Because Pelican Parts supplied the wrong pins I reused the existing ones in the connector. Not perfect but it seems to be working ok. FWiW I always solder where I can.
Old 03-19-2016, 10:59 PM
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I finished installing this but I'm not sure I was successful.

I'm satisfied with the quality of my assembly of the cable connector, but when I crank the motor it still doesn't start. The tachometer needle doesn't move when cranking.

Does this mean I need to take a closer look at the connector I just put together?

Pin1 = white
Pin2 = brown
Pin3 = shielded

I did feel the connectors 'click' when pushing them into the housing. Nothing too difficult in putting it together. Is it possible 3 and 1 should be switched?

Problem is after putting it tougher, it doesn't seem like you can take it apart without destroying it.

Thoughts?
Old 03-20-2016, 12:43 AM
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Just took some pics of my connector. Are you sure the plugs and wires are correct? Did you set the gap for the sensor as per specs?
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