Trying to understand live data

[KierDurrant16]

Can anyone point me in the right direction,

2008 Mercedes Vito 111CDI (OM646)

Is in limp mode, won’t rev about 3000rpm
No fault codes when scanned but live data is showing some odd things

Airflow rate from mass air flow sensor: 246.86 g/s

Catalyst temperature (B1-S1): -40.0^c

Catalyst temperature (B1-S2): 2203^c

Fuel/Air commanded equivalence ratio: 0.999

Equivalence Ratio (lambda) (B1-S1): 0.000

Oxygen sensor voltage (B1-S1): 0.000V

Commanded EGR: 4.7%

EGR ERROR: 99.2%

Barometric pressure: 79kPa

Anyone have any ideas what’s going on….

The only thing my tiny brain has come up with is it’s not getting a signal so it’s assuming worse cases?

The next step in my diagnostic plan is fire

 

[hotponyshoes]

Egr valve stuck/faulty?
Does it dose the black smoke out when driven hard?

 

[Kram]

Rats have eaten the engine sensor loom?

Are the values bouncing around or not changing?

 

[KierDurrant16]

Egr valve stuck/faulty?
Does it dose the black smoke out when driven hard?

EGR removal/inspection is tomorrow evenings job, awaiting e-torx sockets.

Black smoke - yes when driven hard

Rats have eaten the engine sensor loom?

Are the values bouncing around or not changing?

No change at all, tested with ignition on/engine off, idle and through rev range upto 2940rpm (won’t rev any higher).
Other sensors (rail pressure, engine speed, throttle position etc etc) all showing expected values

 

[Kram]

I'd then check any visible areas of wiring, re-seat any connectors looking for corrosion.

I cant remember, was it mercs that used soy based wiring insulation, that rodens liked to nibble?

 

[m_c]

It's been a while since I've worked on that engine.

Lack of DTCs would suggest a more mechanical failure, as some kind of electric failure should set a DTC quite quickly.

Stand out things from that data, is the lack of plausible B1S1 catalyst temp sensor, and the barometric reading of 79kPa.
However depending on the quality of the scan tool, the reported data might not match the PID description, and not all sensors are fitted to all variants.

And another thing of concern, is you mention black smoke. Something that age should be fitted with a DPF, so you should never see black smoke.

What is the history of the vehicle?
There's a few things that are making me think that it's been remapped..

 

[KierDurrant16]

I'd then check any visible areas of wiring, re-seat any connectors looking for corrosion.

I cant remember, was it mercs that used soy based wiring insulation, that rodens liked to nibble?

I’ve checked over a fair bit of the loom and there is previous repairs, I’ve also repaired a wire for the o2 sensor heater element previously.

It's been a while since I've worked on that engine.

Lack of DTCs would suggest a more mechanical failure, as some kind of electric failure should set a DTC quite quickly.

Stand out things from that data, is the lack of plausible B1S1 catalyst temp sensor, and the barometric reading of 79kPa.
However depending on the quality of the scan tool, the reported data might not match the PID description, and not all sensors are fitted to all variants.

And another thing of concern, is you mention black smoke. Something that age should be fitted with a DPF, so you should never see black smoke.

What is the history of the vehicle?
There's a few things that are making me think that it's been remapped..

The scanner is a icarsoft MB 3.0 not cheap generic but by no means brilliant/profressional

Yes to DPF, black smoke was noticed by mother in law on drive home so could have been a tiny bit or plooms!

Unknown regarding remap, it was gutless but being in limp mode is expected



Thank you for the replies, i prefer my vehicles with minimal sensors and flash diagnostic codes!

 

[Nomad]

Random guesses from somebody who has done some diagnostics but never on that van :
Bad earth (engine/chassis or ECU ground) - recheck sensors after connecting a car jumper cable from battery -ve to engine block.
Unplug one of the failed sensors (is MAF easy to access?) and check sensor feed voltage is in spec.
Corrosion causing low power to the sensors (do the "odd" sensors share a supply?)
Corrosion or a loose plug (unplug & reseat ECU connections, check for loose tension on any pins)

 

[m_c]

How long have you had the vehicle?

 

[Moose McAlpine]

EGR removal/inspection is tomorrow evenings job, awaiting e-torx sockets.

Don't expect it to come out easy. OM646 EGRs are notorious for seizing in place, usually being destroyed during removal.