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R34 GTT Manual Code 14 P0500 speed sensor circuit diagnosis help

Annex
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Annex Rookie

Annex

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Hi guys,

Driving along today, my engine light flicked on showing code 14 speed sensor circuit.

It came on when i was cruising in 5th at 70kmh. No noticeable change in the driving experience, no slip light or anything else. Speedo works fine, the only thing that's different is my bulb in the bottom left of the dash has gone.

So I know this is going to be a dumb question but the bulb couldn't possibly be throwing this code? Otherwise I have no clue where to start, apparently this code could be anything along the speed sensing circuit? So speed sensor and wiring back to the ECU etc.

Is there a way to test the speed sensor to see if it's faulty?

If anyone is able to point me in the right direction to start would appreciate it. Cheers

Screenshot_20240521-171551.png

joshuaho96 Veteran

joshuaho96

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Posted
1 hour ago, Annex said:

Hi guys,

Driving along today, my engine light flicked on showing code 14 speed sensor circuit.

It came on when i was cruising in 5th at 70kmh. No noticeable change in the driving experience, no slip light or anything else. Speedo works fine, the only thing that's different is my bulb in the bottom left of the dash has gone.

So I know this is going to be a dumb question but the bulb couldn't possibly be throwing this code? Otherwise I have no clue where to start, apparently this code could be anything along the speed sensing circuit? So speed sensor and wiring back to the ECU etc.

Is there a way to test the speed sensor to see if it's faulty?

If anyone is able to point me in the right direction to start would appreciate it. Cheers

Screenshot_20240521-171551.png

Most likely if the speedo works fine it's the driver circuit in the cluster that takes the VSS signal and converts it into a neater format for the ECU/HICAS/etc. Pull your gauge cluster out and clean the board with contact cleaner, all that fun stuff. Look for corrosion, signs of burned contacts, failed solder joints, etc.

GTSBoy Grand Master

GTSBoy

Posted
Posted

You won't likely find an R34 manual, but the R33 (and probably usefully enough R32, if you know how to infer) manual will tell you how to inspect the speed signal. You will need either consult or an oscilloscope. Now is the time to buy a cheapy scope from aliexpress if you haven't got one. No-one should be without one these days.

Annex Rookie

Annex

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19 hours ago, joshuaho96 said:

Most likely if the speedo works fine it's the driver circuit in the cluster that takes the VSS signal and converts it into a neater format for the ECU/HICAS/etc. Pull your gauge cluster out and clean the board with contact cleaner, all that fun stuff. Look for corrosion, signs of burned contacts, failed solder joints, etc.

Thanks mate, honestly would make sense, I reflowed my gauge cluster solder joints last week after that wasn't working. now it works like a charm 

Annex Rookie

Annex

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15 hours ago, GTSBoy said:

You won't likely find an R34 manual, but the R33 (and probably usefully enough R32, if you know how to infer) manual will tell you how to inspect the speed signal. You will need either consult or an oscilloscope. Now is the time to buy a cheapy scope from aliexpress if you haven't got one. No-one should be without one these days.

I've been looking for an excuse to buy an oscilloscope off ali express. My time is now! Cheers

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