Engine codes after replacing o2 sensors on 1.6 THP 156 DS3

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utdminiman
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Engine codes after replacing o2 sensors on 1.6 THP 156 DS3

Post by utdminiman »

To try and cut a long story short the cars (2011 DS3 1.6 THP 156) had a lot of work done to it lately (timing, clutch, impulse wheel, water pump, thermostat, crankshaft sensor, head gasket etc etc ).

Before the car went into the garage I had bought some parts to give the car a bit of TLC due to it's age (2011) and mileage 85k, so thought I'd give it an oil change, replace o2 sensors, MAP and boost sensor and the boost solenoid to make sure everything was in top shape.

I got round to replacing the o2 sensors (pre and post cat) last night started the car and everything seemed fine. Got to work this morning and the service light and radio warning 'Engine fault: repair fault' popped up when I pulled in. Kept the car running whilst I parked and fished out the OBD2 adapter and the light kept popping up, making the beep noise and going away then popping up again (odd since it usually will only do the beep and warning once and then leave the EML on). In this case only the service light came on and off but it kept beeping each time it came up.

So I checked for codes and found P0171, P0133 and P0134 all pending which would seem like a faulty bank 1 O2 sensor but it's brand new and only done 12 miles on my way to work which would seem odd. The sensor was an ERA sensor matched and checked at euro car parts so should match and be of good quality?

I was planning on going and resetting the codes over lunch, maybe the BSI too if that might help it to trigger it learning from the new sensor. If it's still playing silly buggers I'll try swapping it out for the old sensor once I'm home but if that doesn't work I'm guessing damaged wiring harness maybe (due to the above beeping) unless anyone else has a better idea what's going on?

Cheers
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GiveMeABreak
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Re: Engine codes after replacing o2 sensors on 1.6 THP 156 DS3

Post by GiveMeABreak »

utdminiman wrote:
14 Jun 2022, 10:56
So I checked for codes and found P0171, P0133 and P0134 all pending which would seem like a faulty bank 1 O2 sensor but it's brand new and only done 12 miles on my way to work which would seem odd. The sensor was an ERA sensor matched and checked at euro car parts so should match and be of good quality?
Unfortunately not. ECP have a dire reputation for parts quality and unless you are getting a branded quality sealed OEM part, their aftermarket equivalents don't hold much with members here including myself. It is not unknown for after-market parts to be of poor quality, often dead on arrival or simply fail shortly after.

As you have specified yourself - the faults started after fitting these sensors.....

If you pop up your VIN I can help with the codes - but I suspect it may be down to the actual parts fitted otherwise a heck of a coincidence.
utdminiman
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Re: Engine codes after replacing o2 sensors on 1.6 THP 156 DS3

Post by utdminiman »

Ah shame, I get what you mean with ECP since I bought some coil packs a while back and 3 of them were different brands!

Cheers fort having a look Marc, the VIN is VF7**************[VIN obfuscated, can be read by forum staff].

Edit: The part was genuine ERA, ERA branding on the sensor, sealed in the box, and the box ERA branded and sealed.
utdminiman
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Re: Engine codes after replacing o2 sensors on 1.6 THP 156 DS3

Post by utdminiman »

GiveMeABreak wrote:
14 Jun 2022, 11:14
utdminiman wrote:
14 Jun 2022, 10:56
So I checked for codes and found P0171, P0133 and P0134 all pending which would seem like a faulty bank 1 O2 sensor but it's brand new and only done 12 miles on my way to work which would seem odd. The sensor was an ERA sensor matched and checked at euro car parts so should match and be of good quality?
Unfortunately not. ECP have a dire reputation for parts quality and unless you are getting a branded quality sealed OEM part, their aftermarket equivalents don't hold much with members here including myself. It is not unknown for after-market parts to be of poor quality, often dead on arrival or simply fail shortly after.

As you have specified yourself - the faults started after fitting these sensors.....

If you pop up your VIN I can help with the codes - but I suspect it may be down to the actual parts fitted otherwise a heck of a coincidence.
Doesn't look like it's the new sensor annoyingly. Swapped out for the old one now and same problem with an intermittent service light and engine problem popping up the dash that keeps going away and coming back.

Annoyingly this time round the codes didn't seem to stick around as pending to check them each time I scanned it came up blank. But I'd imagine they were the same codes.

Couple of observations from the test run.

O2 graphs seem to fluctuate as they should when driving and with a 70mph cruise control on. However if I leave it in gear with no gas (eg coasting to a roundabout) both sensors dropped to 0V until I pushed the clutch or the gas

LTFT is also up to +10% with a -15% STFT at idle
wheeler
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Re: Engine codes after replacing o2 sensors on 1.6 THP 156 DS3

Post by wheeler »

What are both the sensors reading with the engine warmed up & idling?
Does your diag show the engine going into closed loop?
utdminiman
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Re: Engine codes after replacing o2 sensors on 1.6 THP 156 DS3

Post by utdminiman »

wheeler wrote:
15 Jun 2022, 06:49
What are both the sensors reading with the engine warmed up & idling?
Does your diag show the engine going into closed loop?
Diag is showing closed loop and once warmed up post cat o2 is flat anywhere from sometimes stays flat showing rich sometimes showing lean, depends if I've just driven it about. Pre cat o2 (the one flagging the codes) seems fine and fluctuating from about 0.1 to 0.7/0.8v although it does seem a bit erratic. Will upload some screenshots when I take it to the shops later.

The on and off of the service light etc only really seems to be whilst driving. When I come to a stop it usually goes away so hard to read any pending codes. The fact it keeps going on and off makes me think it's electrical and since it does it to the new and old sensor now. I think I did tug slightly on the wires accidentally getting the socket of the clip to the engine bay (oily fingers slipping) so maybe that was enough to slightly dislodge one of the wires giving it an intermittent connection

Hopefully my local auto electrical can inspect the socket and lead and replace if not, hopefully not a new harness/loom since that'll be expensive and a ball ache
wheeler
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Re: Engine codes after replacing o2 sensors on 1.6 THP 156 DS3

Post by wheeler »

utdminiman wrote:
15 Jun 2022, 11:38

Diag is showing closed loop and once warmed up post cat o2 is flat anywhere from sometimes stays flat showing rich sometimes showing lean, depends if I've just driven it about. Pre cat o2 (the one flagging the codes) seems fine and fluctuating from about 0.1 to 0.7/0.8v although it does seem a bit erratic.
All of the above is exactly what I’d expect to see from a perfectly working system.
utdminiman
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Re: Engine codes after replacing o2 sensors on 1.6 THP 156 DS3

Post by utdminiman »

wheeler wrote:
15 Jun 2022, 12:17
utdminiman wrote:
15 Jun 2022, 11:38

Diag is showing closed loop and once warmed up post cat o2 is flat anywhere from sometimes stays flat showing rich sometimes showing lean, depends if I've just driven it about. Pre cat o2 (the one flagging the codes) seems fine and fluctuating from about 0.1 to 0.7/0.8v although it does seem a bit erratic.
All of the above is exactly what I’d expect to see from a perfectly working system.
I think that's part of the problem. 90% of the time B1S1 is working fine giving a proper reading, then due to wiring or something else, it will cop out long enough to flag a pending code and give me a light before realising the sensor is working properly again and then removing the pending codes. Yesterdays test with the old sensor I was looking at the RTI o2 graphs which aren't the quickest at updating. Will take it for a drive today with the graphing function up and a faster response time set to see if I can show how the O2 graphs are working with & without the EML flagging.
utdminiman
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Re: Engine codes after replacing o2 sensors on 1.6 THP 156 DS3

Post by utdminiman »

So, took it for a test run, annoyingly couldn't replicate the issue but grabbed some o2 readings anyway, all the screenshots are closed loop reading - I've added a bit of a description to each image for the conditions

The engine is running rich and using more fuel than usual which is part of the reason for replacing the sensor. I was getting around 45mpg with mixed driving (50+ if I'm doing 70 on a motorway stretch) and getting roughly 400-450 miles out of a tank before needing to think about filling up. Now I'm getting 39mpg according to the car and usually the fuel light is coming on at around 325-350 miles which given the price of fuel atm is a bit of a stinker.

As I mentioned the cars had a lot of bits and bobs done to it over the last year / 1.5 years, detailed below from oldest to newest (the first 5 were all done at the same when the engine when completely dead)
New timing chain and accessories, inc head skim new gaskets etc
New thermostat
New clutch, reluctor ring, crankshaft sensor
New camshaft sensor
New MAP and boost pressure sensor
New High pressure fuel pump
Walnut blasting the inlet valves
Spark plugs and coil packs

Basically it seems annoying it's had all that work poured into it over the last year and now I'm getting crappy mileage out of it. The car runs fine although does seem a tad sluggish but I'm guessing that's down to the excess fuel being used by the car. Any ideas would be great because I'm all out for now!
Attachments
Gaps in sensor 1 reading when driving around neighbourhood / pulling into drive
Gaps in sensor 1 reading when driving around neighbourhood / pulling into drive
Pulling into residential area after coasting in gear B1S2 seams to stay low then rise
Pulling into residential area after coasting in gear B1S2 seams to stay low then rise
Steady residential speed of 30mph driving out of my neighbourhood
Steady residential speed of 30mph driving out of my neighbourhood
Driving on the ring road at 70mph cruise control then turning CC off because someone pulled out on me
Driving on the ring road at 70mph cruise control then turning CC off because someone pulled out on me
utdminiman
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Re: Engine codes after replacing o2 sensors on 1.6 THP 156 DS3

Post by utdminiman »

Right so intermittent beeping is back, was on the driveway idling and the light would come and go every 30 seconds or so (link to video: Got the o2 readings up, them seemed fine as above even when the car beeped and when they EML turned off steady fluctuations and steady post cat o2. Idle revs have jumped to 1k revs though, normally idle at around 700rpm which is strange.

Opened the bonnet and it was hot under there, like opening the oven hot, admittedly it's just been driven for 20 mins and its a hot day and a black car but I've opened up the bonnet before and it's not been that hot. Engine it's self seems fine coolant temp reading 80-100 during use, but I've noticed a slight coolant leak and a very slight hissing on the turbo see picture circled, it appears to be coming from the banjo also circled. Is there a chance the coolant leak is causing the turbo to overheat massively which is pushing the o2 sensor near it's upper limit of capability flagging a code and making it go away?
Attachments
turbo coolant leak
turbo coolant leak
utdminiman
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Joined: 26 Nov 2020, 23:11

Re: Engine codes after replacing o2 sensors on 1.6 THP 156 DS3

Post by utdminiman »

The saga continues:
Checked the EML coming into work again today and we have a new code (still can't get P0171, P0133 and P0134 to show up) but the new pending code is now P0341 Camshaft Position Sensor A Circuit range / performance.

Now the camshaft sensor (Bosch OEM per invoice from garage) was changed with the timing. So my think is this might confirm that with all this work done to the car (inc electrical diagnostic) means there is something inherently wrong with the electrics in the car. Alternatively, it could also mean they f*cked my timing chain job.

Although I'm erring towards it being electrical since the faults only come up as pending and for some reason the actual EML doesn't come on it turns on at start up but only the service light turns on when a fault comes up on the radio display, haven't had that happen before.

I know DS3s tend to be a bit picky when it comes to batteries and mine is definitely past its 3 year warranty period so could it be worth replacing that and then looking at taking it back to the garage that 'fixed' my car.