P0A94 2011 4.4 TDV8 Range Rover

Hi Guy's, im after some advice regarding the fault code: P0A94 on a 2011 Range rover

Ive had a google and it only seems to e relevant to electric cars & obviously mine is a dirty diesel.

I would e greatly appreciated if someone can advise me.

Oh & the car turns over ut dosnt fire.

Many thanks in advance

What code reader do you have?

Delphi DS150e I have a mongoose, but can't get it to work.. so im stuck with the Delphi

_ASH_ said:

Delphi DS150e I have a mongoose, but can't get it to work.. so im stuck with the Delphi

Click to expand...

Is that a general diagnostic tool or RR specific?

What is the concern / symptoms? ignore the DTC for now....

Graculus said:

What is the concern / symptoms? ignore the DTC for now....

Click to expand...

Post #1, "turns over but doesn't fire". Out of my area of expertise, I 'll leave it to you as you obviously know the new stuff.

Ah, sorry - speed reading....
There is a DC-DC converter in the ECM but it shouldn't generate any DTC's, so in the absence of meaningful codes - back to basics... anything unusual about the last time it was driven, does the engine sound 'normal' during cranking (too slow or fast, 'lumpy' etc. any warning lights last time it was driven? Following on, is there fuel getting up to the HP pump, at a reasonable flow?

The only DTC that comes close is P0194 - Fuel rail pressure sensor circuit intermittent / erratic signal rate of change above threshold. This can be caused by air being drawn in to the fuel, low fuel level, jet transfer pump in tank inoperable, blocked or incorrectly fitted fuel filter, failed / failing HP fuel pump, defective FRP sensor or poor electrical connection to the FRP sensor. IIRC there was an overlay harness to address the last issue. All the above presupposes the DTC is actually the one I mentioned....

OK, right, I was driving home and suddenly died... only fault code at the time was: P250A (Engine oil level - circuit) & P0195 (Oil temperature sensor circuit), after paying an auto electrician to plug it in, he told me at there was no fuel pressure (Showing 0 mpa in the rail)..

I then ordered and changed the fuel filter, the pressure sensor (Right hand rail at the front), the PRV (Left hand rail at the back & the fuel regulator sensor (on the pump).. I now have around 17 mpa, and a good fuel pressure if I crack an injector.

Anyway, showing 17 mpa (live data) I cracked an injector expecting the pressure to drop, ut it didn't.

I then decided to take the pressure sensor off the rail & left it hanging loose on the wires, and I still get 17 mpa.

Ive checked all the wiring from the sensors to fuses & eco & all seems to be fine.

After trying many many things, clearing faults and re reading them today I get P0A94 and also U0300 faults which has finally made my mind up that its electrical related.


What dosnt help is that my car is at work where ive been ale to do a few bits, but ive been made and am due to leave at the end of the month, so if I can't get it done, I may have to sell it as it is..

Many thanks for any info

Well that's put a bit more meat on the bones!
How handy are you with a multimeter? because you've got some checks to do....
I'm not sure whether the 'parts darts' will have helped or hindered, it reads like there's a resistive joint on one of the ground sensor circuits, but until you can check voltages at the sensors, that's purely a guess.

I'm fairly confident with a multimeter... I've checked the 3 parts for the fuel sensors & they seem to be fine..

I'm just unsure where to check now.

Thanks

Check across the + & -ve wiring at the sensor, should be 5VDC +/- 0.25VDC also check the voltage from the -ve wire to the battery -ve, should be less than 0.2VDC volt drop. Check the supplies to the ECM - should be the same as across the battery - within 0.2VDC. Check them all, not just one - a corroded fuse can give you a relatively small volt drop but will cause big problems!
I'd also suggest checking the supply across the sensors you mentioned had DTC's immediately after the breakdown, they won't have caused the issue but may have some bearing on the cause.
I don't think you mentioned it, what - if any, fuel pressure value were you getting on live values with the sensor unplugged? are you getting any 'short to ground' or 'short to positive' DTC's relating to the fuel pressure sensor with it disconnected?

I have checked the wiring before, ut can't remember the values, so ill check them again..

With there pressure sensor unplugged, im getting 22 mpa (from memory)

Thanks

That's a very high value - and not a default one, did you get any 'short to......' DTC's with it unplugged?
There should be four ground connections to the ECM, physically check the ground stud they're connected to for corrosion etc., everything you're saying so far points to a high resistance sensor reference ground connection.

Has anyone got a ground location diagram (Think its a good way to start), I will also get the readings from the sensors & post

Oh yes, I've been down this road recently my friend. Have a look at these. Zoom in on the connector diagram and you'll see all of the ones prefixed with a black circle are the grounds and their respective connector numbers. Enjoy.

Holy ****.... where do I start.. lol

Is the DS150e genuine or China clone ? Googling P0A94 does return results for various Hybrid vehicles, so either the DS150e is wrong, or the ECU reporting it has a strange fault.

Keith, this is what China DS150e looks like. It's worked fine on most vehicles I've connected it to (except P38).

Right, I've done a bit of digging in my old training docs, the DTC is indeed valid and points to the 5VDC sensor supply outputs
So we're basically on the right lines, just need to refine the testing to the sensor power circuits and ground connections. The 17MPa reading could well be due to the sensor supply being shorted to 12V due to a faulty actuator, an EGR for instance, which has both 12V for actuation and 5V for position sensing (or possibly a failed DC-DC converter in the ECM). So check the sensor voltages, starting with the fuel rail pressure sensor.

pwood999 said:

Is the DS150e genuine or China clone ? Googling P0A94 does return results for various Hybrid vehicles, so either the DS150e is wrong, or the ECU reporting it has a strange fault.

Keith, this is what China DS150e looks like. It's worked fine on most vehicles I've connected it to (except P38).

View attachment 308541

Click to expand...

No idea really, my diagnostic experience is confined to Faultmate and a ELM device for the Transit. Over the years I have read about a few diagnostic devices that mention the P38 but reports suggest they are limited to the V8 engine ECU.