The Cam Angle Sensor (CAS) as a unit consists of three parts. These
are easily viewable on the car when removing the black dust cover.
1) the central spinning notched Reflector Wheel, 2) the Hall Effect
sensor on the bottom which provides the timing reference for the
injection sequence; and, 3) the magnetic pickup for rpm data. See
writeup of repairing the Hall Effect sensor which has great
pictures of these parts.
It is the Hall Effect sensor which causes the engine check light
to come on and causes engine running problems. A Code 41 error is
reported at the ALDL and turns on the engine check light when the
ECM does not receive signal pulses for more than twenty engine revolutions
or it does not receive signal pulses for more than 5 seconds
Lotus have now released a new Hall Effect Sensor, which is available
as a seperate part, the usual price is £97+vat, however Lotus
currently have these on sale (correct as of 08.07.05) for just £20
+vat, you will need to order one through you local main lotus dealer,
part number: A100E0102S. When the item
arrives, you’ll notice that Lotus have taken the opportunity
to redesign it somewhat (see picture below). In the picture, you
can see the old style sensor on the left and the ‘new’
redesigned sensor on the right.
Now, there is a down side to the new HAL sensor and those observant
of you will have noticed the addition of a connector ‘fly’
lead. In order to fit the new sensor, you’ll need to remove
the old wiring loom connector and replace it with the one above.
The sensor kit contains all the instructions, the female connector
and all the necessary crimp pins and weather proofing grommets.
The pictures below show the new sensor fitted to the CAS assembly.
Lets hope this redesigned HAL sensor offers a lasting solution
to our error code 41 problems. After fitting the CAS, complete with
new HES, you need to reset your timing.
Many thanks to Darren, Doug, and others for the pages and writeups that were
combined to make this page. Hopefully I've covered all of the information required
in the update of this page, TStevens.