Engine Check Light - MAF Fault

[graemesmith]

Just washed my 310S (1600 Sigma) and now the Engine Check Light is on permanently.  Comes on Dim when ignition turned on and stays Dim with the engine running.  My OBD2 tester comes up with the generic P0100 Mass Airflow Sensor as a fault code but it won't reset the fault.

The Autel tester I've got wouldn't reset any faults on my wives Fiat either so I'm pretty sure it is cheap rubbish.

Once the car has dried out is there any other way to reset Engine Check Lights with the standard Caterham Sigma ECU?

Not that impressed as it didn't get any wetter than driving in the rain!

[Jonathan Kay]

I haven't seen much discussion beyond this, which includes Caterham's advice.

Jonathan

[graemesmith]

Thanks Jonathan

Remember reading that thread a while ago but couldn't find it again.

Looks like I have a dampness warning light!

Graeme

[simon_h]

Unless they have started selling the eu6 ecu cars in the uk you have no obd as it's an mbe ecu as far as I know. 

I think the mil being on dim is a voltage backfeed and nothing to worry about. The code is for a component uk cars don't have. Only the eu sigma have a maf. 

[graemesmith]

It definitely has an OBD2 port.  Its a 2017 Sigma engined UK spec 310S.  There is a thread on here somewhere about the OBD2 port and mine confirms to the standard logic.  It is behind the knee panel on the drivers side and connects as a 'CAN OBD2' and I can read all the usual live parameters such as RPM etc.

edit - Just checked the SBD Site and the MBE ECU's from 9A-Release-be400 onwards can interface with a standard OBD2 scan tool.

You are correct, it does not have a MAF sensor.  I've managed to identify most of the other bits on the carb and engine body and there is no MAF sensor.  I'll probably invest in a better OBD2 reader as this one caused me hours of heartache last time I tried to diagnose anything with it.

[Dorset AR]

Your car doesn't have a functional OBD port for faults. It will read real time data but will not provide fault codes that mean anything as it's a locked MBE ECU. Only Euro spec cars have one that functions in the way you'd expect. 

The light you can see is caused by a back feed through the tachometer causing dim illumination of the engine check lamp. There is NO check engine light function on a UK spec car other than the Suzuki powered 160. 

There is a modification to prevent it happening but on or not you've not got a fault. How do I know all this, I've just been through it all with my 2016 Sigma powered car. 

Be careful who you take advice from. 

[ChrisC]

You need to check the type of ECU fitted.  If it's an MBE it won't do OBD, only CAN from the OBD2 port.  I have a  2017 duratec with MBE, and only a MBE lead from SBD dev can read / log all the live parameters using Easymap software.  It's locked so you can't change anything.   Have a look at the MBE ECUs on the Caterham parts website, does it look like them?

it is possible there is a new ECU given the variable valve timing stuff, I haven't seen anything posted on here to suggest either way, and if a new ECU is being used if it can OBD (or not).  I know the 160 does.

[graemesmith]

It looks like the standard Sigma ECU's on the website.  I'm not really interested in what it can, or cannot do via the OBD port, I just popped a scan tool on to check the idle RPM as the Tacho said 1200 but the scan tool says 850 which is probably closer.  The code came up when I did a fault scan just to see if it would work.

The OBD scan tool appears to be communicating using the CAN protocol via the OBD port as you say as it runs through various protocols to try and communicate finally settling on 'CAN OBD2'.  It gives me what I want so I don't need to delve into Easymap.

The Engine Check Light seems to be a red herring.  I have only done 390 miles so far and I always saw 2 bright lights when I switched the ignition on and both went out after start.  This time I saw one bright and one dim which sent me down this path.  Having played about a bit I now realise that the 2 bright lights were the battery and brakes.  The handbrake was off in the garage so only the battery light lit up bright!  Never actually noticed the colours or I would have realised this much sooner.

As with the ear plug mod for clunks and rattles I'll probably go for the black tape mod for the light if it gets annoying.

 

[ChrisC]

The only tool that can easily read / decode your ECU fully comes from MBE, just don't waste to much more money finding that out ;-)

850 rpm if true maybe is too low, and I agree the tacho is more of a reference tool, just like the rest of the instruments.  850 might explain the dimm charge light, but I would have expected you also to have stalling when cold and other related issues.  

I want to point out all my Sigma experience is based on the 125, 150/140 cars not the newer model, so who knows 850 may be correct, but seems low for a cars with a cam upgrade.

[graemesmith]

Thanks Chris,  I'll email Caterham for some definitive advice.

[graemesmith]

Got a definitive answer from Caterham.  No Sigma models have the Check Engine Light implemented as has been previously stated in this thread.

I'll just have to ignore it!