Intermittent MIL - Code 41

[nhaynes]

Hi all,
I've got an intermittent MIL with no engine misfire or stumble.
The only significant work I've done recently is to fit a new SJS stainless exhaust system (same dia as the original OEM system so shouldn't affect the wastegate). I SORN my Elan for 6 months during Winter and she had 49,615 genuine miles so is now starting to suffer low mileage age related issues.
I've done the paperclip diagnostic and DTC 41: engine speed, cam angle sensor error is recorded. This clears if I disconnect the battery but it does come back after a few minutes of further driving. The MIL does not stay on but goes off after a few minutes suggesting an intermittent brief loss of cam angle position. I've removed the cam angle sensor connector, the connector and harness both seem good.
I'm thinking of buying a replacement Hall Effect cam angle sensor from SJS as it's only £39.75 but before doing so, though I'd post to see if anyone else has experienced similar problems and if see if anyone has items to test other than simply switching cam angle sensors.

[Rambo]

Have you checked the cambelt tension Neil? From memory, someone told me if it's too slack it can affect the fine tolerances within the CAS and send incorrect info to the ECM re engine speed/CAS setting

If you keep throwing up error code 41, and you have checked the cambelt tension and it's OK, the HES is worth trying and/or replacing. Kathryn had a problem at Castle Combe about 3 years ago and Dapinky removed her CAS and we tried out my spare HES to see if it made a difference. Again, from memory, I think it confirmed her HES was faulty. These HES's were on the Lotus aftersales list for many years at ~£20 so it might be worth checking if there are any left. And, at the same time, check the CAS 'o' rings and replace if required - the rubber suffers from age related hardness (Dapinky kindly replaced 1 of mine at CC that was weeping)

If you can't get an HES via whatever source, you can borrow mine to check out your CAS/HES problem

[nhaynes]

I've finally completed a bit of work on my Elan this year after suffering a Code 41 intermittent MIL last season.
I changed the cam belt, water pump, idler, tensioner and auxillary belts. They'd only done 5,000 miles but were due a change as they were 10 years old. Anyway, everything that came off was in excellent condition but I still had the MIL Light Code 41.
So changed the Cam Angle Sensor and this fixed the issue in an instant. Good to know for any future Elaners with the same issue. Steve at SJSportcars sells a replacement for £49.75. The connector is different from the original so you need to cut off the original connector and splice the new one onto the original harness, quite straightforward.
Neil.

[Tuga2112]

Have you checked the cambelt tension Neil? From memory, someone told me if it's too slack it can affect the fine tolerances within the CAS and send incorrect info to the ECM re engine speed/CAS setting

If you keep throwing up error code 41, and you have checked the cambelt tension and it's OK, the HES is worth trying and/or replacing. Kathryn had a problem at Castle Combe about 3 years ago and Dapinky removed her CAS and we tried out my spare HES to see if it made a difference. Again, from memory, I think it confirmed her HES was faulty. These HES's were on the Lotus aftersales list for many years at ~£20 so it might be worth checking if there are any left. And, at the same time, check the CAS 'o' rings and replace if required - the rubber suffers from age related hardness (Dapinky kindly replaced 1 of mine at CC that was weeping)

If you can't get an HES via whatever source, you can borrow mine to check out your CAS/HES problem

just for future reference.
i have had my cambelt slip and be 2 tooth off. the engine light did not came on. take this comment with a grain of salt given my experience.