2.8 Crd P0235 Code And Other Stuff.

[frogland]

Ive just been given a 2006 LX 2.8 CRD with 124000 kms and im quite happy with it.

There are issues and i know Im going to have to invest a bit of time and money.

 

So I did the key dance and got code P0235 : Boost sensor Ive located it and it seems brand new. EGR valve ? TURBO ?

 

Im having intermittent starting problems,I turn the key the engine fires up for a second and then cuts out other times it starts fine.

Im presuming its a fuel issue the fuel filter heater housing plug is not connected,i havent reconnected it and it hasnt any signs or burn of deterioration.

 

Im going to try and test the pressure release valve and change the fuel filter, things which are simplest first.

 

The warning water in fuel filter symbol comes on as well as the engine warning and an airbag warning.I emptied the fuel filter a little but still get the warning.

 

The previous owner told me the car seemed to lacking its punch of old,i cant tell. 

 

Any pointers ? The simplest first .

[QinteQ]

You are correct in assuming fuel first as it turns [battery] and starts, so its  (1) Fuel, (2) Fuel or (3) Fuel. It can and frequently be dirty filter, water contaminated filter, air in, vacuum loss, etc. Pull the NEG from the battery for 16 minutes to reset [you won't lose the radio code] your P codes. Put a new diesel filter in, watch for x2 '0' rings and double check the white plastic water drain on the bottom is fitted tightly and does not rattle, then thoroughly check all lines & pipes, put the filter heater power plug back and reconnect the NEG cable. Push the hand primer pump [central twixt RAD & grill till its hard and primed. Start car, does it ?. That primer should be hard every morning after being parked up, if it isn't its back to air in, vacuum loss, connections. Best of luck.

[frogland]

Ok great.

Funny you should mention the hand primer since i used the car for two runs today with about a 4 hour gap in between on both occasions i hand primed beforehand and the car started fine i did also keep my foot on the accelerator at the same time.

It's worth noting that the primer wasn't hard, so fuel pressure wasn't being maintained !

[mikebh8]

Hi, do you hear the prime pump running when key turned to on position, it is above the fuel filter and it should run for a while.

On mine, I fitted a hand prime pump (it didn't have one to start with) but after running the car and turn it off, it wasn't hard, also with the engine of (mind your eyes when doing that), after a while if the pressure release valve attached to the fuel rail is pressed, there will be no pressure in it.

I'm not arguing the above diagnostic but I had few cars with hand primer fitted, on all (if I rember well) the primer was soft on touch with the engine off. If you have access to a difderent car that has one, like Peugeot xsara pocasso, Citroen 5, try and see for yourself I may be wrong.

 

Hope it helps.

[mikebh8]

I have just checked the Autodata and the code you gave is related to boost sensor but the suggestion is wiring, you saying it is new, I assume the fault was investigated before however, try the fallowing:

 

pin 1 and 4, with engine idling you should have 1.6V

pin 1 and 4 with engine at 2500rpm, it should read 2V.

The above test is to check the signal

Let us know the results and we will see from there.

 

Hope it helps.

[gordy]

If your engine is cutting power on booting it then returning after reducing throttle after about 20 seconds its the Turbo actuator. P0235 like mine. Down back of engine I'm afraid or up from below.

[frogland]

Thanks all this info is taken on board and i'll keep you informed.

[frogland]

Had a bit of time this morning : Fuel pressure release valve at end of rail is not leaking.

Engine has started every time when foot is pressed on throttle,still cuts out after a second without throttle.

Hand primer on filter housing doesn't get firm with engine running !

Is there a specific procedure related to fuel filter replacement,is it best to refill new filter beforehand ?

It's normal that i can't accelerate above 2500 rpm stationary ?

 

Thanks.

[mikebh8]

The acceleration on idle is normal, something related to the engine's safety.

Mine has the fuel filter bellow the fuel tank, is yours in the engine compartment?

If the car came with a hand primer you don't have to fill the filter, you prime it afterwards.

There is a topic related to throttle position sensor, see if your fault applies.

[QinteQ]

Accelerator RPM is 'governed' @ idle, so normal. You clearly have as stated an LP issue of leaky housing, pipes, as stated. I've only ever came across one single 2.8 with rear filter, and electric lift pump ever. Priming after filter replacement is as mikebh8 says using the hand primer. Watch out for double 0 ring and water trap tightness and check pipework for leaks.

[frogland]

The fuel filter is in the engine bay.

The housing plug and socket show absolutely no signs of damage,but there could still be a crack ?

I've ordered a filter and will remove the housing at the same time and keep you up to date.

 

I presume that when I go through all the hassle of of getting to the back of the engine I should do the calorstat,turbo and egr at the same time ?

[mikebh8]

To do the turbo and/or egr is not a cheap deal, you could remove them and clean them properly,inspect the pipes for dirt and debris, watch for play in the turbo. It is a good practice to replace them but mind the costs, plus the English say: if is not broken don't fix it.

 

Plus faults related to turbo or egr are very notable, black smoke if they're blocked, white smoke if they leak and absorb the oil into the engine.

 

Hope it helps.

[frogland]

The thermostat has never been replaced and I've heard that it's a weak link or at least one of them ?

[QinteQ]

The thermostat has never been replaced and I've heard that it's a weak link or at least one of them ?

It's a DIY 15 minutes and 15 quid, look for 'inline stat mod' 100% effective. If you flush the RAD & matrix never back flush and always use HOAT, the car will self bleed through the open filler hole.

[QinteQ]

The fuel filter is in the engine bay.

The housing plug and socket show absolutely no signs of damage,but there could still be a crack ?

I've ordered a filter and will remove the housing at the same time and keep you up to date.

 

I presume that when I go through all the hassle of of getting to the back of the engine I should do the calorstat,turbo and egr at the same time ?

Calorstat, you must indeed be French my friend !

 

Andy and the stat here

[frogland]

Replaced the fuel filter,starting slightly better but not perfect.

Primer pump still not staying firm.

I going to remove the housing to check for cracks but there's no fuel coming out from there and no signs of damage to plug.

I f that's not the cause what next , injectors ?

Could the P0235 code (boost)and the fuel problem be connected ?

[frogland]

It starts first-time-every-time i open the throttle upon ignition.

If I can be sure there's no connection between the two issues I'll focus on the boost issue first.

I've ordered some extra fine multimeter probes to test the boost sensor,if it's not a wiring/ecu issue I'll start looking at the turbo.

Edited August 13, 2017 by frogland

[8953lewis]

Hi

I'm sure there was a post on here with similar issues turned out to be the fuel pressure regulator valve. Got to be worth a shot rather than spending hundreds getting the injectors checked they are about £40 on good old eBay.

Mark

[frogland]

I've already checked it and it's not leaking,it was easy to do so that's where i started.

[frogland]

I have just checked the Autodata and the code you gave is related to boost sensor but the suggestion is wiring, you saying it is new, I assume the fault was investigated before however, try the fallowing:

 

pin 1 and 4, with engine idling you should have 1.6V

pin 1 and 4 with engine at 2500rpm, it should read 2V.

The above test is to check the signal

Let us know the results and we will see from there.

 

Hope it helps.

Hi I've received the new probes for my multimeter so i'm going to be able to carry out this test.

I presume you mean the pins on the plug whilst it is disconnected from the sensor ?

Pin 1 is the earth right ?

cheers.

[frogland]

I got this idling and and at 2500rpm.

[frogland]

I also got this reading.

[ryden]

Looking at the second reading you have - 4.48v between pin 1 & 3 suggests an open circuit ( bad connection, corroded pin, chafed wire, broken wire) But that's just utilising the Chrysler diagnostic manual. 

 

Out of curiosity, have you had the boost pressure sensor out and checked if its gummed up ?

Edited August 21, 2017 by ryden

[frogland]

I've checked the sensor and it's ok.

Checking for damaged wires would mean opening the loom and following them to ?? Do they go to the ecu ?

I'm tempted to disconnect the Ecu and give it a go with contact cleaner,whats the procedure ? batterie earth plug off first and then disconnect the plug.

[mikebh8]

Hi, I was rechecking the fault code you posted... my apologies for not looking properly

It turns out to be twice one after another in the same list of faults.

So, first is ( same fault code as I already said) P0235 MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR A, TC SYSTEM- (cause) CIRCUIT MALFUNCTION (I can only assume it can be related to the wiring of the other one)

The second time is: TURBOCHARGER (TC) BOOST PRESSURE SENSOR A/ SUPERCHARGER (SC) BOOST PRESSURE SENSOR A- CIRCUIT MALFUNCTION - WIRING TC/SC BOOST PRESSURE SENSOR

 

Inspection is to be made with the plug in and as stated before, two tests, one at idling and one at 2500rpm and my guess is that boost sensor is sensor A in the circuit.

 

 

The way I see a circuit is like the a staircase light switches, they are in parallel although  in series. After a lot of investigation I found out that on a car it is not everywhere in the electric circuit 12V (nothing new as probably many already know and it is assumed so), however if a contact or a part of the circuit does not operate as it should, it can be that a sensor ( in this case yours) sends to the ecu a message, the ecu works that message ( which can be a resistance, capacitance, voltage and others) and according to that gives commands to other components in the circuit so eventually it closes or opens whatever the driver and/or the engine requires. In your case, it is only an assumption as I'm not an expert, the sensor instead of sending a figure like 1.6v back to the ecu, it only sends 0.8 or 0v, in that case the ecu takes the message as an error ( really inside the ecu are many switches that close and open as per voltage ore resistance input) and it does not send a command forward. For these models ( I have a 2.5 crd, but they are more or less the same), the injectors to open, it is needed 0.8 Volts ( not a lot isn't it).

Now, if a fault occurs, the ecu acts the same as the immobiliser, it will shutdown the components trying to protect the engine or other components that are at risk. So long story short, in your case could be that when you activate the throttle position body, it sends a bit more information to the ecu and bypasses the fault turning off the fuel pump and/or injectors, which are the main parts turned off by the immobiliser.

 

 

Note, "the water in fuel" on your dash... at the fuel filter casing, do you have more than one plug, if not the existing plug has more than two wires? if it doesn't have does not mean the two wires are for the same circuit, one can be the signal for the heating and the other one could be for the water in fuel... try reconnecting the plug and see if the light on the dash( well more above the dash but that's not the point) turns off.

 

Hope it helps.

[mikebh8]

I also got this reading.

I have answered the question, please re due the tests with the sensor connected. You can pinch the wires with the probes and after the test/s is done isolate the holes.

Pin one is blue, pin 4 is blue/yellow

Edited August 21, 2017 by mikebh8