Throwing codes

Hi,

I almost didn't want to start another thread, but I feel like this is going to take a while to get sorted and thought it might be of interest. Here’s what I’m dealing with currently:

Around 300 or 400km ago, my car went into limp mode accompanied by an ESC error. Sorted itself out after a 15-minute pause. About 150km later, limp mode occurred again, but this time there was no ESC warning. The Check Engine Light (CEL) remained persistent even after restarting the car.

Car drove fine until after the second start (?) since CEL it sounded like a tractor, almost stalled while idling, and required a good push on the gas to get it rolling (Had to get it off the street into the gerage). In gear it "worked" to some extent, but definitely not in a good way.

Followed the manual to dis- and reconnect the battery. CEL and limp mode were still present, although the car ran "normal" again. I drove it to the dealer, and at some point, the limp mode disappeared. The dealer read the codes and surprisingly found nothing except for a "Mechanical failure Start/Stop button." Cleared the codes, and I was back on the road.

The next day, when I started the car, the CEL reappeared. Frustrated I decided to purchase an OBD reader to gather more information. Here are the codes I obtained:



Brought it back to the dealer who did update the ECU (I originally was scheduled for a later date) and cleared the codes yet again.

Drove another 40-50km and after a pull in 4th gear from 60km/h to around 110km/h, the CEL came back. New codes:



Anyone wanna guess while I’m waiting for an appointment to get this properly checked out? Seems to be somewhat related to bank 2(?)..

The car idles kinda rough, but it always did that to some extent as far as I can remember. I know it can idle super smooth since I wondered if it was actually running a time or two because it didn’t generate any vibration whatsoever

I’d be running diagnostics on the heated oxygen sensor on bank 2 to see if it’s responding correctly — wiring to and from it as well all the way to the ECM. Every single error you’ve shown is showing some issues keeping air fuel mixture correct and everything is reading rich.

If one more person says this is a battery issue, I’m gonna lose my shit. Harry did a huge disservice to this community brushing off issues on low voltage problems.

Next up: power steering and paint problems — low voltage.

Edit: Sorry if this comment seems out of place, I’m just reading various issues and everyone is parroting the same line about the battery. Don’t parrot things, use your brain and come up with a diagnostics / test plan instead of jumping to conclusions and solutions.

kitkat said:

If one more person says this is a battery issue, I’m gonna lose my shit. Harry did a huge disservice to this community brushing off issues on low voltage problems.

Next up: power steering and paint problems — low voltage.

Edit: Sorry if this comment seems out of place, I’m just reading various issues and everyone is parroting the same line about the battery. Don’t parrot things, use your brain and come up with a diagnostics / test plan instead of jumping to conclusions and solutions.

Click to expand...

It does seem to be a catch all to these cars. I mean come on! Its not the catch all for Lotus, these cars are having massive issues. Ive never owned a car that low voltage was an issue, and I own a Lotus.

Have a problem? Oh ok I reccomend checking ALL the grounds and taking your battery out, oh its showing 100%? still the battery.

Some of you guys need to grow up. Weak batteries are a known issue, and it's something that's relatively easy to eliminate FIRST, before you get into troubleshooting things that are not so easy to look into. I used to troubleshoot electronics for a living, and you quickly learn the KISS principle; Keep It Simple Stupid. Start with the obvious, and go from there.

With electronics, it was power supply, which at that time included fuses. I saw guys spend hours, tearing apart units, replacing switches, power supplies, rectifiers, component after component trying to figure out why it wouldn't turn on. They never bothered to check the fuse. I remember one guy who finally came over to my work area, and asked me if I'd help him troubleshoot a unit he'd being doing this to. I went over, took a pair of needle nose pliers, bridged the fuse holder and the unit turned on. The fuse was bad. That was the problem all along. The look on his face was priceless. I actually felt sorry for the guy, but that's how you learned.

In the OP's case here, the error codes definitely show something's wrong at the engine or the cat, or possibly even both. I'd check all the connections related to bank 2. Look for scorch marks on any of the connectors. Check the sensor wires. Look for wires that have rubbed through and are intermittently grounding on what they were rubbing against. If everything looks good after that, check the fuel sensor, check the injector, check the oxygen sensor, especially the wiring for it. Since the wiring is coming off a catalytic convertor, that's a source of very high temperatures. It could be the oxygen sensor is flaky.

These kinds of things can be tough to troubleshoot, but be methodic. Start with a plan, and work step by step, eliminating one thing after another as you work through it. Don't assume; check, even if it looks like it's okay. Make sure that part isn't the problem before moving on to the next thing.

New set of codes, thrown immediately after starting:

I'm awaiting an appointment (Public holiday today) to get this thoroughly checked, but it might take a long time. Dealer is packed with new Emiras and said something about 30. June or July - I sure hope it was the former
Anyone can assess how bad it is to drive in this state? It runs fine, especially if it warmed up a bit - but I don't want to cause any damage in the long run. Would suck to miss the beginning of summer tho

Kimmax said:

New set of codes, thrown immediately after starting:
View attachment 26719
I'm awaiting an appointment (Public holiday today) to get this thoroughly checked, but it might take a long time. Dealer is packed with new Emiras and said something about 30. June or July - I sure hope it was the former
Anyone can assess how bad it is to drive in this state? It runs fine, especially if it warmed up a bit - but I don't want to cause any damage in the long run. Would suck to miss the beginning of summer tho

Click to expand...

You can drive with O2 issues without a problem. My understanding is that a car is drivable with the CEL on. If the CEL starts to flash, then you must not drive it or you'll risk damage.

If there's actually an issue with the pre-cat HO2S sensor I would not be driving it.
I controls the stoichiometric mixture, which means you could be running rich or lean. Based on your post-cat O2 sensor it sounds like you're running rich.

By driving you could be:
- Damaging your cat
- Adding carbon deposits

kitkat said:

If there's actually an issue with the pre-cat HO2S sensor I would not be driving it.
I controls the stoichiometric mixture, which means you could be running rich or lean. Based on your post-cat O2 sensor it sounds like you're running rich.

By driving you could be:
- Damaging your cat
- Adding carbon deposits

Click to expand...

That's what I expected. I'll stay put until the mechanic calls back on Monday..

Kimmax said:

That's what I expected. I'll stay put until the mechanic calls back on Monday..

Click to expand...

A CEL is yellow warning for a reason. You're not in imminent danger of hurting anything, especially if it's just an O2 sensor. If people stopped driving a car every time an O2 code flashed, the highways would be littered with abandoned cars. You are absolutely fine for a short period of time (2-300 miles), so enjoy your weekend and get it fixed on Monday. BTW, pre-cat O2 failures fail-safe to rich to avoid damaging the engine. Your converter might run hot, but it'll straighten itself out after you put the new sensor in.

I did a few kilometers, part good and running as calm as never before (I suspect that's the fail-safe) and some feelable rough.
Wanted to drive it to the dealer this morning and well..

(Fuel trim)


Needless to say, I did not drive like that. Switched off, let the ECU settle for an hour, and tried again - "ran" again.
Car is now parked at the dealer who tries to do something between jobs, otherwise, I'm looking at the last week of June

Kimmax said:

I did a few kilometers, part good and running as calm as never before (I suspect that's the fail-safe) and some feelable rough.
Wanted to drive it to the dealer this morning and well..

(Fuel trim)
View attachment 26869

Needless to say, I did not drive like that. Switched off, let the ECU settle for an hour, and tried again - "ran" again.
Car is now parked at the dealer who tries to do something between jobs, otherwise, I'm looking at the last week of June

Click to expand...

Wow those wild short term fuel trims. If you wanted to figure out exactly if it’s the HO2S or the wiring, you could probably swap the sensors.

If it swaps banks you know it’s the sensor itself.

Update to who's interested:
Dealer confirmed it's the O2 sensor. Apparently, there was some communication with Lotus HQ too. Mechanic said they have to get approval from HQ before starting any work since they want to know everything about problems found - guess that's a good thing.
New sensor was ordered (In stock ) and is due to be installed in the next week

Kimmax said:

Update to who's interested:
Dealer confirmed it's the O2 sensor. Apparently, there was some communication with Lotus HQ too. Mechanic said they have to get approval from HQ before starting any work since they want to know everything about problems found - guess that's a good thing.
New sensor was ordered (In stock ) and is due to be installed in the next week

Click to expand...

So glad for you! Should be a quick fix too, I looked it up and they’re pretty easy to access.

O2 sensor in stock from Toyota?

digilotus said:

O2 sensor in stock from Toyota?

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Apparently it’s a custom Bosch one. My dealer couldn’t find another one matching except from Lotus itself.

Some of you guys need to grow up.

$100k. Car fails first week. ‘Stop being such a pussy, suck it up” . Am I reading your note correctly eagle?

Kimmax said:

Apparently it’s a custom Bosch one. My dealer couldn’t find another one matching except from Lotus itself.

Click to expand...

Well that's disturbing. That means they'll be more expensive than Toyota ones.

Car is back an home and, arguably, runs better than ever. Absolute smooth idling and no more hiccups. Of course my opinion is biased, but glad it got sorted relatively quickly

Well it was fun while it lasted. Throwing new codes, limp mode, parking brake service, didn’t want to start, etc.
Guess it’s time for an ECU replacement and harness check -_-
Dropping it tomorrow for the 5th or 6th time at the dealers..