38mpg at 70mph. 2004 C5 estate 110bhp

[torq]

Lexia results!

Just ran a diagnostic, a few faults came up, suspension, clocks, mf screen and of course injection system!

"Temporary Fault, accelerator pedal jammed (v84 ->). Strategy Active

Ecu fault code. P2299

Which the internet says is

"Brake Pedal Position / Accelerator Pedal Position Incompatible "

Anyone any idea what this means in the real world, outside the Matrix??

Thanks.
T

Any ideas?

[Citroenmad]

It could be something silly like the accelerator pedal had been pressed with the engine off or something.

I guess your suspension fault was the steering wheel angle sensor? Same thing usually, if the wheel has been turned while the engine/ignition was off.

What was the faults with the MF screen and injection system?

[torq]

I had only 5 mins to run the test, wife had me on the clock, so I didn't get to check everything.

But once the kids are in bed and she's watching x factor I'll get to have a proper test and let you know.

T

[torq]

Well, after X factor I went out and cleared all the faults. 2 days and 70 miles later I've no injection faults. I have still a suspension fault and yep it's the steering wheel angle sensor, not too othered by that at the moment.

But I still have 3 dash related faults. All remote and intermittent.

"Engine speed incorrect value received"
"Coolant temperature incorrect value received"
"Vehicle speed incorrect value received"

So will the above, though working and not giving injection faults, pass incorrect values to the ECU and result in incorrect fueling?
Or do just have a faulty dash?

Also I can't add in cruise control as it doesn't appear to be an option on my BSI and the bracket for the 2nd brake switch doesn't have the hole or space to add one.

[Citroenmad]

Your C5 isnt a hydractive+ and probably doesnt have ESP, so the steering angle sensor has little effect.

It seems there is a sensor, or a few, amiss somewhere. Did you clear those codes and they returned?

I added cruise control to my 2004 2.0HDi 110 VTR C5, it had the second brake switch already installed. Your BSI will have the function, I think the option is found in the injector menu, and you also need to tell the car somewhere else that it has cruise. Possible the module under the steering wheel.

[torq]

http://www.frenchcarforum.co.uk/forum/v ... hp?t=37185

Looks like they are phantom faults so it's back to the drawing board. I'm going to have to go old skool on this an look outside the controled electronic part of the fuel system for the problem. Starting with sticking brakes, followed by dirty leaking injectors and take it from there.

T

[torq]

I added cruise control to my 2004 2.0HDi 110 VTR C5, it had the second brake switch already installed. Your BSI will have the function, I think the option is found in the injector menu, and you also need to tell the car somewhere else that it has cruise. Possible the module under the steering wheel.

Yep. Activated the cruise control option in the "injection" ecu and it's working perfectly now. Pity there's no light on the dash to remind you that it's on, my wifes merc is the same.

Maybe this weekend I'll get to have a poke around the engine for the cause of the bad mpg. The economy suffers when the engine is under load but on the flat at 70mph the realtime gauge is giving around 47mpg, any pressure on the pedal or a slight upwards incline will see it drop to low 30's.

Changing the air and diesel filters and a can of "diesel purge" have made no difference.

[Citroenmad]

Nope no light on the C5I but the facelift versions have a display in the mileage screen which says what speed its set to. It works slightly differently too. A very nice feature to have, I don't like being without it now.

Is that the instant MPG you are watching? Mine drops to 30's if its going uphill or im accelerating slightly.

[torq]

Nope no light on the C5I but the facelift versions have a display in the mileage screen which says what speed its set to. It works slightly differently too. A very nice feature to have, I don't like being without it now.

Is that the instant MPG you are watching? Mine drops to 30's if its going uphill or im accelerating slightly.

My last 2 cars have had cruise control and I now can't live without it!

It's the instant I'm watching.

Left battery disconnected for 2 hrs to reset the ecu but has made no difference. Mpg being reported at 40.9 over the last 200 miles at an average of 67mph.

But I can say it's not brakes as I can easily push the car with the handbrake off. It's not the throttle position sensor (pedal) as the same symptoms occur with cruse control.

Tonight I'm getting the "bosch yellow jacket" common rail and diesel engine management books down for a good read.

[Paul-R]

Tonight I'm getting the "bosch yellow jacket" common rail and diesel engine management books down for a good read.

Wooof, you won't be needing your Horlicks then...

[cachaciero]

FWIW I believe that the computed values of consumption are very accurate and on a good engine will match the consumption figures as calculated by measuring fuel put into tank and mileage. The only thing that the computer doesn't, can't, measure is the actual amount going through the injector(s) there has to be in the calculation a value for injector conductance which of course will be based on those values obtained from a good injector. So if the mileage obtained from the trip computer differs markedly from that calculated by burning of a known amount of fuel then I would suspect the injectors, for most of what else could go wrong in the injection system the ECU will post an error message. Having said that I'm not sure that it would pick up low boost pressure as an error, and I do wonder about the situation where more than one sensor is within it's tolerance band but all at the wrong end as it were, i.e slightly high fuel rail pressure coupled with slightly low boost pressure would give a poorer fuel consumption while individually being within spec.

cachaciero

[torq]

The trip computer and the "fill to fill" method are both giving approximately the same values so the actual fuel system is functioning correctly. The previous owner had the head skimmed etc so I'm starting to think that the problem cold be related to this. It's possilble that the timing wasn't set correctly when the head was replaced, that a vacuum pipe has been left off or incorrectly fitted. I can hear a slight whistle when on the road so could be a turbo problem though the car pulls well and had no lag.

The bosch book says the ecu responds to a request for torque from the throttle or cruise control and delivers fuel accordingly. When going downhill the real time mpg can go up to 90+mpg or higher as there is no load, it's only when the load is introduced that things go wrong.

Map sensor fault? ERG fault? As cachaciero suggests, I'm not getting any faults but that's not to say that the sensors are functioning correctly.

[torq]

Interesting...

Just found this http://www.aa1car.com/library/map_sensors.htm, not Citroen but the same logic applies

[Paul-R]

MAPs are for petrol not diesel so nothing applies I'm afraid.

[torq]

MAPs are for petrol not diesel so nothing applies I'm afraid.

Acording to the citroen parts catalogue, the dw10ated engine has a MAP sensor. It's hosed to the top of the intercooler, part no 1920gh.