Citroen C4 Adblue delete
Discussion
safesurfer said:
The Urea engine warning light has come on, on my Citroen C4 Gran Picasso which can be an expensive fix.
I've been quoted £400 for Adblue delete in the Aberdeen area ? Does that seem reasonable ?
Cheers
Did you do it? I'm looking at getting mine done but want to know the implications.I've been quoted £400 for Adblue delete in the Aberdeen area ? Does that seem reasonable ?
Cheers
Vanewb said:
safesurfer said:
The Urea engine warning light has come on, on my Citroen C4 Gran Picasso which can be an expensive fix.
I've been quoted £400 for Adblue delete in the Aberdeen area ? Does that seem reasonable ?
Cheers
Did you do it? I'm looking at getting mine done but want to know the implications.I've been quoted £400 for Adblue delete in the Aberdeen area ? Does that seem reasonable ?
Cheers
perfectly reasonable car, cheap to run utterly ruined but a stupid system built on top of it for a questionable reason.
£400 seems a bit steep you can get it done in Inverness for between £180 to £250.
For those bleating about it been illegal, without interrogating the Ecu no one will ever know it's been deleted, will.pass an MOT no problem, I've gutted DPFs and they've still passed MOTs.
As for insurance I can assure you no assessor is ever going to bother interrogating the ECU on an otherwise standard looking car.
For those bleating about it been illegal, without interrogating the Ecu no one will ever know it's been deleted, will.pass an MOT no problem, I've gutted DPFs and they've still passed MOTs.
As for insurance I can assure you no assessor is ever going to bother interrogating the ECU on an otherwise standard looking car.
AdBlue & EGR delete – emissions tested, results in, Euro 6 is a scam
Here’s some actual data from someone who’s just done it — not hypotheticals, not pub talk, not Facebook-tier “my mate says.”
Vehicle & context:
Citroën C3 Picasso 1.6 BlueHDi (DV6C engine, post-2015 AdBlue variant)
61k miles, full service history, runs clean, zero oil consumption between changes
I do all maintenance on schedule: oil & filter (Castrol Magnatec 0W30 C2 with PSA B71 2302 & 2312) every 6 months, air filter, fuel filter once a year
Timing belt, water pump, and tensioners done at 57k
No issues except the AdBlue system — a stupidly complex mess of sensors, heaters, level senders, and ECUs that eventually will fail.
What I had done:
AdBlue delete (software only)
EGR delete (software only)
Left DPF and regeneration system fully intact and functional
No increase in power or torque requested — this is a daily runabout, not a McLaren F1
The work was done by someone who’s been mapping ECUs for 15+ years — not some laptop cowboy. No hacks, no guesswork.
Emissions test – BEFORE & AFTER (same garage, same machine, 30 mins apart):
NOx – identical
CO – unchanged
CO₂ – unchanged
Opacity – zero
Smoke test – passed clean
The technician said — and I quote — “You’ve not deleted anything, this is cleaner than half the new diesels we see.”
EGR delete – why it’s better for the engine:
EGR is a stupid band-aid on combustion inefficiency. It:
Feeds carbon-laden exhaust back into your intake
Gums up valves and ports (particularly bad on direct-injection engines like the DV6)
Creates soot load and turbo lag at low RPM
Causes twitchy throttle and irregular combustion at low load
Since the delete:
Throttle response is smoother and more predictable
No more low-speed hesitation or micro-judder in traffic
Engine sounds quieter, feels more refined
MPG up 2–3 depending on drive cycle
This is with DPF still in place and no tune changes.
MOT & legality:
UK MOT testers cannot plug into the ECU or scan for AdBlue or EGR status. The criteria are:
No warning lights
No excessive smoke
DPF visibly present (check with a mirror)
DPF regen still functions? ✅ Yes.
Unless you tell them, they’ll never know — and unless your engine’s running like a steam loco, they won’t care.
The Wynns AdBlue additive question:
Here's your answer.
Crystals = contamination. AdBlue is already corrosive, hygroscopic, and temperature sensitive. Introducing additives into a delicate SCR system is playing roulette with your injectors and tank sensors. Snake oil at best. Expensive system failure at worst.
Bottom line:
AdBlue and EGR systems exist purely to tick Euro 6/7 boxes in a lab — not because they make the real-world emissions better.
The fact that I deleted both and saw no change in actual measured NOx, CO, CO₂ or opacity confirms what many of us suspected:
Euro 6 is a compliance scam that makes engines worse, not cleaner.
Deleting AdBlue and EGR on a well-maintained car with a working DPF is the rational choice if you care about long-term reliability, cost, and actual emissions.
Happy to answer technical questions if anyone's interested.
Here’s some actual data from someone who’s just done it — not hypotheticals, not pub talk, not Facebook-tier “my mate says.”
Vehicle & context:
Citroën C3 Picasso 1.6 BlueHDi (DV6C engine, post-2015 AdBlue variant)
61k miles, full service history, runs clean, zero oil consumption between changes
I do all maintenance on schedule: oil & filter (Castrol Magnatec 0W30 C2 with PSA B71 2302 & 2312) every 6 months, air filter, fuel filter once a year
Timing belt, water pump, and tensioners done at 57k
No issues except the AdBlue system — a stupidly complex mess of sensors, heaters, level senders, and ECUs that eventually will fail.
What I had done:
AdBlue delete (software only)
EGR delete (software only)
Left DPF and regeneration system fully intact and functional
No increase in power or torque requested — this is a daily runabout, not a McLaren F1
The work was done by someone who’s been mapping ECUs for 15+ years — not some laptop cowboy. No hacks, no guesswork.
Emissions test – BEFORE & AFTER (same garage, same machine, 30 mins apart):
NOx – identical
CO – unchanged
CO₂ – unchanged
Opacity – zero
Smoke test – passed clean
The technician said — and I quote — “You’ve not deleted anything, this is cleaner than half the new diesels we see.”
EGR delete – why it’s better for the engine:
EGR is a stupid band-aid on combustion inefficiency. It:
Feeds carbon-laden exhaust back into your intake
Gums up valves and ports (particularly bad on direct-injection engines like the DV6)
Creates soot load and turbo lag at low RPM
Causes twitchy throttle and irregular combustion at low load
Since the delete:
Throttle response is smoother and more predictable
No more low-speed hesitation or micro-judder in traffic
Engine sounds quieter, feels more refined
MPG up 2–3 depending on drive cycle
This is with DPF still in place and no tune changes.
MOT & legality:
UK MOT testers cannot plug into the ECU or scan for AdBlue or EGR status. The criteria are:
No warning lights
No excessive smoke
DPF visibly present (check with a mirror)
DPF regen still functions? ✅ Yes.
Unless you tell them, they’ll never know — and unless your engine’s running like a steam loco, they won’t care.
The Wynns AdBlue additive question:
Here's your answer.
Crystals = contamination. AdBlue is already corrosive, hygroscopic, and temperature sensitive. Introducing additives into a delicate SCR system is playing roulette with your injectors and tank sensors. Snake oil at best. Expensive system failure at worst.
Bottom line:
AdBlue and EGR systems exist purely to tick Euro 6/7 boxes in a lab — not because they make the real-world emissions better.
The fact that I deleted both and saw no change in actual measured NOx, CO, CO₂ or opacity confirms what many of us suspected:
Euro 6 is a compliance scam that makes engines worse, not cleaner.
Deleting AdBlue and EGR on a well-maintained car with a working DPF is the rational choice if you care about long-term reliability, cost, and actual emissions.
Happy to answer technical questions if anyone's interested.
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