Peugeot 508 Sw 2.0 HDi 16v - 508SW 2.0 HDi 16v Random Stalling at Idle. - Ed_Reid

Hi, for about the last 12-15 Months my 508 Sw has had a weird issue, intermittent stalling when stopping at traffic light the rev counter gives a small blip and then the engine just dies. No faults are showed on the display no warning lights etc., Car restarts first turn of the key and stalls again unless I give it some revs and hold it above 1000rpm, idle does sit at 900 cold or about 750 hot. It is totally random when it will do it, but if it does it once it will do it 4 or 5 times, restart fine on the key. just Weird, I have had a full service done inc fuel filter still does it. The car is a 2012 508 Sw Active 2.0 Hdi. My Vin is VF38ERHF8CL033315

I have bought the download tool with pp2000/diagbox checked. couple of codes store. Maybe some one can explain the last one.

B1825: Oil level information fault. Level too low (now top up to max mark on dip stick was in-between min and max)
B1418: Fault in status of seat belt fastening information for determining the presence of the driver. (I was now wearing the seat belt at the time)
B1816: Fault loss of the hybrid drive train status information (Then again its not a hybrid)

U1F00: Fault event not stored in the fault log.

I cleared 4 codes which where in it. Changed the filters again and starting using BP ultimate Diesel and it was fine for a while. You could still see the revs drop every now and again but the computer would catch it. but this morning it stalled about 6 times in a row. the only code stored is in the BSI module code is B162C 12 Fault Accessories Positive Relay Control & Status not coherent. If you clear it and retest (with out starting the engine ) code stays cleared same with starting and stopping the engine on the key. but if you let it stall/cut out the same error code appears again.

After doing some google research, I came across some C5 owners (same engine) who were having stalling issues, like mine no engine management lights/weird error codes etc..Mines only had (BSI or body system codes apart from the U1F00 code still don't know what that is) Turned out for some of them, the air control units were dirty (also called by some sites and you tube the throttle body), So I stripped mine off, really easy 2 electrical connection, two T30 screws one T30 that you don't take right out and disconnect the air duct and a small vacuum tube. Inside my air control unit was very dirty. thickly coated in oil and dirt/carbon from the EGR and Breather tubes. The Air Temp Sensor you could not even see due to the Grime. So I cleaned everything out and reassembled. Used the Peugeot Planet tool to reset everything and did the actuator tests etc.. Car is running fine at the moment but only time will tell..

I did notice when its at idle every 30 secs or so you can hear and feel the air flap open and close does this exactly 5 times in a row like open close wait a sec open close wait a sec 5 times then idles perfect for approx. 30 secs then does the 5 open close cycle again. suspect this is the EGR Valve

Left the car at idle for about 30 with the Peugeot planet connect. No issues.

guess what still stalling. Unplugged each sensor on the air side from maf right up to air pressure sensor one at a time. Each one gave a P???? error code and made no difference. so cleared codes, unplugged EGR valve plug again no difference. and again cleared the codes. HELP...


Peugeot 508 Sw 2.0 HDi 16v - 508SW 2.0 HDi 16v Random Stalling at Idle. - elekie&a/c doctor

U codes are an electronic network fault,not particularly related to engine faults.Have you had the injectors tested?.Any excess return spill could cause the fuel pressure to drop sufficiently to cause a cut out situation.Could still be an egr fault,although may not flag a code.Just a thought.

Peugeot 508 Sw 2.0 HDi 16v - 508SW 2.0 HDi 16v Random Stalling at Idle. - Ed_Reid

Injectors where tested all ok no leak back spray pattern was fine also. Egr has been blanked to see if that was the cause. nope still done it. The car has plenty of power. Economy is great too. Last summer I went from Glasgow to Nottingham then Windsor then down to The Lizard in penzance on One tank of fuel and still had just under a quater of a Tank, over the last 5800 odd miles the car has returned over 47Mpg thats a mix of every type of driving/road/speed. I think thats great for a car that size. It only does this at idle, there is a slight delay if you plant your foot to the floor before the revs climb. I have checked all the vaccum hoses just in case. Nothing. Surely some one has had this problem. even on another diesel car which uses the same engine. Peugeot just did the normal when it was under warratty, no codes no parts. and then started suggesting that they all did this due to "economy modes" needless to say I have not been back. So i'm starting to think. Fuel regulator valve, High pressure pump some sort of fuel related issue.

Peugeot 508 Sw 2.0 HDi 16v - 508SW 2.0 HDi 16v Random Stalling at Idle. - elekie&a/c doctor

Not too long ago,diesel engines were very simple with very little or no electronics.Modern diesels are a very complicated mix of mechanical and electronic components ,far more than any petrol engine.Running tolerances are highly critical on these diesel engines,and it only needs something to be slightly "off beat" to make the engine run poorly or cut out.Throwing expensive parts at a car hoping for a fix is not the way forward,you can't guess anymore.Your problem of stalling/cutting out is proving very difficult to pin down,and unless the live data from the engine can be read while the fault is occuring, to see what is failing,I think you may have a large task.Although it does appear to be a fuel related issue ,I would not bank on it.I wonder if there could be a problem at the rear of car,related to tank pick module?Does this model have an in tank pump?

Peugeot 508 Sw 2.0 HDi 16v - 508SW 2.0 HDi 16v Random Stalling at Idle. - hardway

Go into P P live data in graph form display and graph the fuel rail pressure,

store/record it and check for dips in the waveform.

Peugeot 508 Sw 2.0 HDi 16v - 508SW 2.0 HDi 16v Random Stalling at Idle. - Ed_Reid

Thanks for the advise hardway, I could not work out where diagbox puts the live data, so I have video'd the screen and uploaded to youtube at

You can see the fuel pressure jumping and dropping before it stalls out 2 or 3 times, So I held the revs up and you can see the pressure jumping about.

First chance I will get the fuel regulator removed and check the mesh on it. I hope its that and not the injector pump.

So what do people think it could be.

Peugeot 508 Sw 2.0 HDi 16v - 508SW 2.0 HDi 16v Random Stalling at Idle. - hardway

You running the RHF system,

most of the fault diagnosis I've done on these are on RHR,

which suffer from pump internal collapse,

so I can only advise my next steps.

open up the fuel filter and check in the bottom for metal debris,

Seldom checked when doing a filter change.

If there is it's bad news,

But I'll take a shot that theres none and it's clean.

you could be right,

could be the fuel pressure reg,

but PP,

check for injector correction values,

I have had these doing crazy things with injectors seem to be heat related but they can go open and dump the fuel pressure,

fine when they cool back down.


PP and injector correction values,

they should all be more or less the same figure.

Let me know what you find in the bottom of the fuel filter housing.

Peugeot 508 Sw 2.0 HDi 16v - 508SW 2.0 HDi 16v Random Stalling at Idle. - Ed_Reid

Thanks for the advise hardway. Today was my first day off work (yep new years day), Drained diesel from filter housing, no debris in jar, Open'd filter houseing and replaced filter and o-ring, checked bottom of filter house , no debris of any sort so bleed the system. Had a look to see where the fuel pressure regulator is. behind air filter box looks really hard to get to. I wonder if is easier to get to it through the passenger side wheel well, (after removing wheel arch liners). Has any one done one of these on a 508 or another hdi engine. The Part is a peugeot/citroen 193339 I believe the delphi part number is 9109-927 same as used on c4, 307,308,407 and funny enough a suzuki jimny.

Thanks for the advise so far.

Peugeot 508 Sw 2.0 HDi 16v - 508SW 2.0 HDi 16v Random Stalling at Idle. - hardway

No debris is good news,

no pump break up.

Check the injector correction values in PP.

If you have in intermitent injector fault the Fuel injector correction value will be different from the others.

I had one of these where I had to rig up an injector leack back test using to tubing from my tester but then ran it into 4 small diet coke bottles rip tied to a plank.

Started it and sat back and watched,

For 15 min's nothing then the uneven idle started.

then one of the injector bottle started to fill so fast actual measuring was not needed.

but it was something around 3 injectors leak back 25 mm,

bad injector around 150mm just measured with a rule on the side of the bottle.

Odd thing was leave the car for 20 min's or so and the bad injector "healed"

It would start and run with no performance issue,

Until 15 min's passed,

A little uncanny!

A Looooong leack back test is easier to do than screwing around with wheel arches.

I sit back and have a quiet cupa and a smoke with a eye on my makeshift leak back tester fluid level.

Peugeot 508 Sw 2.0 HDi 16v - 508SW 2.0 HDi 16v Random Stalling at Idle. - Ed_Reid

Hi your reply came through after I was out. Todays adventures with the pug..

had a quick look behind the passenger wheel, while an inspection lap was put in front of the FPR, could I see it, not a chance. So went in through the top, out came the airbox, maf sensor and next bit of the air duct. Unclip then feed and return fuel hoses, undid the electrical connections on the Bracket and removed the 3x13mm Nuts and removed the bracket. Using a mirror with lots of lighting. a lot of swearing I wish I was double jointed at times. I got the FPR out. Remove the o-ring at the nose of it and took the mesh filter off. looking through it with light behind it you could see that more than half of it looked milky/whiteish ?? Bad fuel at some stage ??? cleaned it with contact cleaner till it was spotless and refitted, new o-ring on nose and refitted. Start to Finish almost 3Hrs not a easy job. Bleed fuel system and started engine. still a bit rough at times, So used the PP to tell the ecu that FPR had been replaced, after that silky smooth. Took the car for run, no stalling, fuel pressure at idle should be about 230-250bar it stayed very close to that range no massive ups or down. During the drive I watched the pressure it stayed very close even right upto 1500-1600bar. When slowing down it stayed nice smooth no roughness. I will try it over the next few days and see what happens.

Thanks for the advice.


Peugeot 508 Sw 2.0 HDi 16v - 508SW 2.0 HDi 16v Random Stalling at Idle. - hardway

Good work!

As stated not a fun job,

not that I was trying to avoid it but as I have to charge I couldn't justify 3+ hours to a client without the tedious test sequence first.

You wouldn't be chuffed with a bill for that and no progress on the fault.

This time you hit it though.

Oh and your milky white is going to be water contamination related.

Modern deisel engines live or die on the frequency of filter changes.

I ignore reccomended and tell owners fuel/oil filters minimum once a year for regular mileage,

It's a lot cheaper than the alternative.

Peugeot 508 Sw 2.0 HDi 16v - 508SW 2.0 HDi 16v Random Stalling at Idle. - Ed_Reid

Ohhh the tales of woe continue...not as bad. has cut out twice in 3 days. same thing on PP fuel pressure jumps about before dropping below 70 bar the engine cuts out.. but not as quick lots of time to catch it and get the revs up. but still not right. check the injector reading all very close to each other. does not sound like its missing more like running out of fuel type noise and actions. I have ordered up a FPR (from a jimny half the price of the peugeot one.. same delphi part number and same connection) which I will change if for no other reason than peace of mind just incase it has an internal fault. The car is going anyway in March, but my best mate says he would like to buy it (funny enought he was the person using it when it first started all this). If I cant get it cured before march I will use it as the trade in, been given a price of £7500 which seems okay for a 3 1/2 year 56000 mile car. At least changing the FPR swap will be quicker this time....I hope.

Will keep you informed of the progress.



Peugeot 508 Sw 2.0 HDi 16v - 508SW 2.0 HDi 16v Random Stalling at Idle. - hardway

It really doesn't take much to drop the rail pressure on these,

The return rail like you've been chasing or as suggested an internal fault on a single injector.

I guessing you don't have access to an occilliscope and low amp clamp so 'scoping the injector amperage waveform is out.

That would be on my list of tests.

So I'm back to making up a large bottle leakback tester,

All it takes is some tubing to fit the plastic return pipes on the injector heads,

4 soft drink bottles,and a clamp for the return line.

Fit it and start it up and sit back and watch.

IF there is an injector flooding it'll drop the fuel pressure just like yours is.

And the evidence will be one of the bottles will be a whole lot fuller than the others.

A little cost test and more than worth doing if for no other reason it rules out internal injector faults.

Peugeot 508 Sw 2.0 HDi 16v - 508SW 2.0 HDi 16v Random Stalling at Idle. - Ed_Reid

Just a quick update, New Fuel Pressure Reguator arrived on Thur so got fitted on Friday, much quicker this time just under 2hrs. Reset the ECU. So far 300 Miles of stop start driving, stuck in traffic.. basically I have been doing anything I can to get the car to stall. but so far its been perfect. no hunting up and down, no stuttering and pressure is within 3bar at idle.

Will post up once sure fault is fixed. I expect if I do 1000 Miles of all types of driving and still have no problems then fault is fixed.


Peugeot 508 Sw 2.0 HDi 16v - 508SW 2.0 HDi 16v Random Stalling at Idle. - stisum


could you please confirm, did replacing the Fuel Pressure Regulator solve the problem?

I'm experiencing the same issues, so I would like to know if there is a valid solution.



Peugeot 508 Sw 2.0 HDi 16v - 508SW 2.0 HDi 16v Random Stalling at Idle. - Peter.N.

I was going to suggest the pressure regulator but as I have had no experience with 16 valve engines I kept quiet but I have had all sorts of running problems on the 8 valve due to the pressure reg.

Glad you get it sorted anyway.

Peugeot 508 Sw 2.0 HDi 16v - 508SW 2.0 HDi 16v Random Stalling at Idle. - Michael Tarpey

OP did you get this sorted, if so, what was the issue


Ask Honest John

Value my car