Speedometer problem
Discussion
Hi, can anyone help with a quick question, the speedo on my 420R has stopped working, is this a common problem and is there a typical fault? I used to see this on quite a lot of track day hire Caterhams which I drove until I decided to get one of my own which made me think there may be a common problem. It's very irritating especially on public roads. although I mainly use it on the track.
Any advice much appreciated.
Any advice much appreciated.
To expand on the above...
There's a toothed wheel on the o/s rear hub. There's also a bracket close by that holds the speed sensor. Jack the car up and turn the wheel, and you should see a little LED on the sensor flash as the wheel spins. If not, slacken off the nut holding the sensor and move it towards/away from the toothed wheel (with it spinning) until you see the LED pulse. Once you get a good position, tighten the retaining nut and go for a drive.
If no LED pulse at all, then your sensor is duff.
There's a toothed wheel on the o/s rear hub. There's also a bracket close by that holds the speed sensor. Jack the car up and turn the wheel, and you should see a little LED on the sensor flash as the wheel spins. If not, slacken off the nut holding the sensor and move it towards/away from the toothed wheel (with it spinning) until you see the LED pulse. Once you get a good position, tighten the retaining nut and go for a drive.
If no LED pulse at all, then your sensor is duff.
My 2012 car's speedo also failed this week 
I've done a bit of digging and hopefully the following info will be useful for anyone else is in the same position ie having to replace a duff sensor......
There are two types of sensors, pre 2017 and post 2017. The older one is quite unreliable hence it was changed to a new one which is thinner than the older M8 (?) one. If you look on CC's website there are two different sensors listed, a '2017' one (300A0019A) and a 'de Dion' one (CAT-SP-0038AK). They are both the post 2017 sensor and despite having different part numbers, the sensors themselves are identical.
One comes with the top hat adaptor and nut, one doesn't. Depending on which sensor you're trying to replace will determine which you need but if you're in any doubt get the CAT-SP-0038AK one, as it's cheaper and comes with the extra adaptor bits.
Finally, there's an additional earth lead, part number 30L229A. I've been told by Chris at Redline that this is to help make the pre-2017 sensor more reliable and isn't needed for the post 2017 sensors.
I've done a bit of digging and hopefully the following info will be useful for anyone else is in the same position ie having to replace a duff sensor......There are two types of sensors, pre 2017 and post 2017. The older one is quite unreliable hence it was changed to a new one which is thinner than the older M8 (?) one. If you look on CC's website there are two different sensors listed, a '2017' one (300A0019A) and a 'de Dion' one (CAT-SP-0038AK). They are both the post 2017 sensor and despite having different part numbers, the sensors themselves are identical.
One comes with the top hat adaptor and nut, one doesn't. Depending on which sensor you're trying to replace will determine which you need but if you're in any doubt get the CAT-SP-0038AK one, as it's cheaper and comes with the extra adaptor bits.
Finally, there's an additional earth lead, part number 30L229A. I've been told by Chris at Redline that this is to help make the pre-2017 sensor more reliable and isn't needed for the post 2017 sensors.
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