Throwing codes

So based on the info the sensor is sending the ECU, it's sending either too much or too little fuel to that bank. In @Kimmax 's case, the fault codes followed the sensors when they were switched to the other bank, so it's not the wiring or the ECU. Now we're down to the sensors. I swear it sounds like defective sensors, except it's odd that the symptom is repeatable, even after installing new sensors. Anybody got a picture of one of these sensors? Do they have manufacturing info data printed on them?

EFE said:

1200km from our home in England

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Try reading the live data using the OBD Dongle, look for Fuel Trim, and see if it reports jumps on that bank. If it does, read the live data of the O2 sensors. Mine showed faulty data there even before ECU codes were raised. "Car Scanner" for iOS (Or Mac, way easier to read) has a live data function if your app doesn't.
Also if you want a replacement car call RA earlier than later, they are a pain to work with in 9/10 calls.
If it turns out Lotus is producing faulty sensors or something is damaging them we're gonna have a big problem. I don't trust Lotus to fix something like that in a timely matter.

Kimmax, Thank you for your feedback.
I pulled fairly detailed data from the fault codes but not live data. Lotus Lucerne did pull live data which showed over fuelling on bank 2 which was the sensor reporting lean burn. The sensor when removed was black and sooty as were the tail pipes from the exhaust.

On the drive across France we realised we had a worsening problem as I had to reset the engine light twice. (Detailed fault report downloaded and sent to Lotus Silverstone)
Warning signs on dash, reduced power before car entered limp mode and ran rough with a slight smell of fuel before eventually spluttering to a stop and not wanting to restart. At which point it appeared to be flooded with a stronger petrol smell.

Not sure what condition the catalytic converter will be in after eating that rich mix.

I suspect as the O2 sensor became more choked and called for more fuel, falsely reporting lean burn to the ecu on a more regular basis.

The team at Lotus Lucerne confirmed via live data that it was running rich on bank 2 and not lean. They swapped the sensor out of their stock Emira and it was still burning rich.

As they have had a public holiday today nothing has happened but tomorrow they will be back on it. I am wondering if the ECU needs time to learn from the new O2 sensor and remap and change the mix.

Apparently the O2 sensor is not the same as that fitted to the Evora or Exige.

Lotus Silverstone had previously checked with Lotus Tech on the engine lights and fault codes I have been occasionally getting and they said it was a false reading caused my voltage and / temperature at the O2 sensor and a new software update would cure the issue.

If that is the case then that false reading might still be causing the ecu to pump extra unwanted fuel to balance the lean mix being falsely reported. That condition in turn could burn out the sensor and potentially damage the cat.

I read on another Lotus forum that a similar issue was resolved with a new ECU.

EFE said:

Kimmax, Thank you for your feedback.
I pulled fairly detailed data from the fault codes but not live data. Lotus Lucerne did pull live data which showed over fuelling on bank 2 which was the sensor reporting lean burn. The sensor when removed was black and sooty as were the tail pipes from the exhaust.

On the drive across France we realised we had a worsening problem as I had to reset the engine light twice. (Detailed fault report downloaded and sent to Lotus Silverstone)
Warning signs on dash, reduced power before car entered limp mode and ran rough with a slight smell of fuel before eventually spluttering to a stop and not wanting to restart. At which point it appeared to be flooded with a stronger petrol smell.

Not sure what condition the catalytic converter will be in after eating that rich mix.

I suspect as the O2 sensor became more choked and called for more fuel, falsely reporting lean burn to the ecu on a more regular basis.

The team at Lotus Lucerne confirmed via live data that it was running rich on bank 2 and not lean. They swapped the sensor out of their stock Emira and it was still burning rich.

As they have had a public holiday today nothing has happened but tomorrow they will be back on it. I am wondering if the ECU needs time to learn from the new O2 sensor and remap and change the mix.

Apparently the O2 sensor is not the same as that fitted to the Evora or Exige.

Lotus Silverstone had previously checked with Lotus Tech on the engine lights and fault codes I have been occasionally getting and they said it was a false reading caused my voltage and / temperature at the O2 sensor and a new software update would cure the issue.

If that is the case then that false reading might still be causing the ecu to pump extra unwanted fuel to balance the lean mix being falsely reported. That condition in turn could burn out the sensor and potentially damage the cat.

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Don't clear the codes, especially if you run into codes related to the O2 sensor. If the ECU detects it's sending bogus data it might ignore it and default to fail-safe values. Might include limp mode or rough operation, but protects the engine. At least that's the logical thing I'd expect to happen. Low voltage / HO2S not up to temp are exactly the codes it had thrown at me too. Also bank 2. Pretty sure we're onto something bigger here - don't like that

Kimmax said:

Don't clear the codes, especially if you run into codes related to the O2 sensor. If the ECU detects it's sending bogus data it might ignore it and default to fail-safe values. Might include limp mode or rough operation, but protects the engine. At least that's the logical thing I'd expect to happen. Low voltage / HO2S not up to temp are exactly the codes it had thrown at me too. Also bank 2. Pretty sure we're onto something bigger here - don't like that

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Is it the same bank for everyone reporting this issue? It would be worthwhile to see how close the VIN numbers are between those reporting this problem, because not everyone is having it. Bad batch of sensors? ECUs? When were the cars built that are showing this symptom? Same day? Same shift?

For there to be only a certain number of people to be having the same problem, there has to be something in common about their builds.

Some data I pulled at fault

P2272 - O2 Sensor Signal Biased/Stuck Lean Bank 2 Sensor 2

Freeze frame :

Calculated load: 33 %

Coolant temperature: 88 °C

Fuel rail pressure (gauge): 351 kPa

Intake manifold pressure: 56 kPa

Engine rpm: 1856 RPM

Vehicle speed: 55 km/h

Ignition timing advance for cylinder 1: 34.5 °

Intake air temperature: 16 °C

Air mass value: 22.44 g/s

Absolute throttle position: 21 %

Time since engine start: 843 sec.

Commanded evaporative purge: 0 %

Fuel level input: 82 %

Ambient air pressure: 100 kPa

Battery voltage as seen by the engine ECU: 14.06 V

Absolute engine load: 35 %

Commanded equivalence ratio (Fuel system): 1

Relative throttle position: 7 %

Outside temperature: 16 °C

Absolute throttle position B: 54 %

Absolute throttle position D: 29 %

Absolute throttle position E: 14 %

Commanded throttle actuator position: 11 %

Vin: SCCLEKAX4PHM11093
Build approx second week of Feb 23
Delivery 14th April 23
First fault with this code after 56 miles on second day of ownership
Always on battery conditioner when parked and run in strictly to code.

Thank you for all of that! Now let's see if others are having trouble with bank 2 sensor 2, and when their car was built.

Eagle7 said:

Thank you for all of that! Now let's see if others are having trouble with bank 2 sensor 2, and when their car was built.

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Mine’s bank two. Build before Dec 22.
SCCLEKAX1PHR10479

These guys are so amazing and are everything you could hope for as ambassadors for Lotus and Caterham.

sensor was bad and they new sensor needed to have an ECU reset to stop the over fuelling

Back on the road again

Ok, so this sensor issues needs sorting and our holiday got off to a very bad start but now with four alpine passes under our belt I have a smile so wide! The way this car drives is sublime….. as I said to my girlfriend we all have faults but I still love my Emira and you darling

Hope the rest of your trip goes flawless!

I would feel happier with a couple of spare O2 sensors in the boot.

I’m up & running again as well.
Hope it survives more than 4 days this time

Seems like a lot of issues are battery related. Wonder if there is a battery-drain issue that's plaguing the Emira. Has anyone noticed quicker-than-normal battery drain on their cars?

Kimmax said:

I’m up & running again as well.
Hope it survives more than 4 days this time

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What was the diagnosis? New O2 sensor and reset the ECU?

EFE said:

What was the diagnosis? New O2 sensor and reset the ECU?

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New sensor, updated everything there is, and full ECU reset + relearning of the exhaust valve