fault code 42.car drives normal

[chetepongo22]

The light is on almost every time,sometimes no.The car appears to drive normal, maybe if the light is on it runs a little less and burns more petrol,no overboost or jumps,it runs normal.I made the clip and code 42.Sparks replaced...what else could I do?the car has 103000kms

[theelanman]

42 Electronic Spark Timing circuit

replace hall sensor??????

A100E0102S HALL SENSOR ASSEMBLY £18.28

from your local Lotus dealer......

[chetepongo22]

I didn't! I will get one!I hope this could fix the problem.

[pineapplecharm]

Sorry to bump but I haven't seen anyone else online mention a confirmed case of curing Code 42 by replacing the CAS. Until I did mine this weekend. Fault gone.

I'm usually unadventurous when it comes to fixing things without a good idea that they're broken but I can confirm that, on this occasion, Code 42 was cured with a new sensor even though I had never specifically had a Code 41.

[texaselite]

I can't say the same.

Originally had Code 41, replaced CAS. It was fine for a little bit. 500 miles later getting code 41 and 42. Replaced CAS again, and still getting 41 and 42!

[Brit-Car-Nut]

I can't say the same.

Originally had Code 41, replaced CAS. It was fine for a little bit. 500 miles later getting code 41 and 42. Replaced CAS again, and still getting 41 and 42!

Did you replace the CAS or the HES? If you replaced the CAS, did you use a NEW CAS or a used one?

[texaselite]

Sorry, meant replaced HES

[Brit-Car-Nut]

Good to know. There was a post a while ago where a member changed the adjusment of the HES and that seemed to clear up his issues. I will try to open up a new cas and measure the clearances as a starting point but you might find the replacement HES needs a tighter clearance. The new HES uses a different plug, so maybe the actual sensor is also a little bit different. I will also try to find the instructions that came with the earlier replacement HES (before they supplied a kit with the plug) just to see if Lotus had anything else to contribute.

[Brit-Car-Nut]

I got a free minute so pulled out a NEW CAS.

Pictures can be viewed here:

The HES is mounted so that the interrupter is closes to the middle pickup post. It almost touches as the flag goes past it.

The Speed Sensor is mounted so the air gap is 0.008" between the snout and the wheel.

The HES on the original unit is self contained including the plug. The replacement HES has a pigtail wire that ends with the plug.
Based on that, the picture "HES hanging OK?" is basically correct but I would find a way to secure the plug so it can't move around.

I will try to dig out a replacement HES and install it on a used CAS to see if there are any fitment differences

[pineapplecharm]

I had codes 41 and 42 for some time. Interestingly I found very little discussion of code 41 anywhere but replacing the coils and HT leads appears to have fixed it. I was getting some funny hesitation under load which cleared up too, hurrah.

Problem is the HES/CAS code 42 which simply will not die. It's not on all the time but usually comes on when starting the engine from warm, e.g. pulling away after filling up. It doesn't seem to affect the performance - no rev limiting, no hesitating or anything.

As everyone says, this is classic and simple so I replaced the CAS before doing the coil packs.. to no avail. It was the first time it had been done so I put on the new connector and so on. Unfortunately I apparently am an idiot and, despite being sure I triple-checked it, I managed to wire the thing backwards, giving a nice spark when I flipped the ignition. Moron. Anyway, putting it back together properly was less exciting but I still had intermittent code 42. Figuring I fried the new sensor I sent off for a second new sensor which I fitted last week and... still code 42.

Did I damage the ECU? I did didn't I. Must I just tape over the ECL?

[Enright]

I don't think you'd have damaged the ECU or it probably wouldn't fire up at all (or you'd get an equally unfriendly code saying "hello, I am dead")!

However to get rid of the code you probably need to disconnect the battery for a while - I didn't see if you'd done this already or not.

By the way can you put your location in your profile please? Currently we can't even narrow you down to your nearest ocean, let alone another nearby owner!

[rip]

I don't think you'd have damaged the ECU or it probably wouldn't fire up at all (or you'd get an equally unfriendly code saying "hello, I am dead")!

When I suffered a failed ECU & the CEL stayed on permanently & would not respond to Elanscan, Tech 1 or a paperclip. It stayed in limp home mode, setting the idle to 1400 rpm & limiting boost to 0.4 bar
If the ECU is aware of an internal fault it will show code 51.

Your fault sounds different to either of the above so I think your problem lies elsewhere.

[Brit-Car-Nut]

To try and clarify your previous comment, I believe you have replaced the HES, not the CAS. The HES would have required a wiring modification while a CAS repacement would have just needed to be plugged up after installation. You would have needed to reset your timing after either operation, so verify that you have done that.

After your earlier questions, I looked up all of the fault codes and code 42 is for a bad HES while code 41 is for a bad speed signal. They don't mean the speed sensor for the speedometer (behind the dash), they mean the OTHER sensor in the CAS. That is the "Speed Sensor" for the ignition system. That sensor rarely fails but the connection could be dirty as could the connection going to the ignition control module or the ICM itself. For the details on testing Code 41, look at this: http://www.lotusm100.com/LEC/Code-41.pdf

If you are still getting a code 42, have you verified the clearances between the reluctor (wheel) and the sensor? Have you checked ALL of the grounds / earths EVERYWHERE? See paragraph 4 of the test sheet.

Here is the testing section for Code 42: http://www.lotusm100.com/LEC/Code-42.pdf

I would also consider that the Ignition Control Module is damaged and that might be something you should replace. I am not trying to make you buy one, but I have a few yet for $70.00 + postage. viewtopic.php?f=129&t=23175#p294448

Your location would be helpful so that someone nearby might be able to offer a test component to verify what is causing the issue.

[GeoffSmith]

By the way can you put your location in your profile please? Currently we can't even narrow you down to your nearest ocean, let alone another nearby owner!

I'll take a punt on Slough (or thereabouts).

[pineapplecharm]

Brit Car Nut, thanks for the list of options. I did disconnect the battery and do so often as it's garaged away from home and I don't want the alarm to infuriate the neighbours! I will get stuck into that test sheet when I have some time next weekend. Thanks.

I wasn't previously aware the CAS and HES weren't the same thing, which gives you an idea of how seriously to take my ramblings.

I'm in Hammersmith, although I do spend time in Slough occasionally! Nice to know I have a stalker.