Discovery 3 TDV6 Limp mode

[Dashing]

Hi, I recently bought a Discovery 3 TDV6 with faults, it would intermittently go into limp mode. This would happen repeatedly and not clear until you left it overnight then it could be ok for 1500km faultless.
The stored code when I bought it was

P0191-24 (28) Fuel rail pressure sensor
range/performance - General signal
failure
- signal stays high

I replaced the alternator when I bought the car as it had failed and also replaced the fuel filter. I drove it for 1500km and then it went into limp mode whilst driving on the freeway. This was code

P2290-00 (2F) Injector control pressure
too low

After lots of research I removed lots of plugs and earth points to check for corrosion but all was good. I then replaced the High Pressure fuel pump believing that was the issue. I then drove it for another 150km and it went well, I then had issue starting it and it cranked over for a long time before starting. It idled fine but I couldn’t drive it more than 100m without going into limp mode. This is the codes I got.

P0087-00 (2F) Fuel rail/system pressure
- too low

P2290-00 (6C) Injector control pressure
too low

I had it towed to Land Rover and a few days later they had a look at it and it has run fine, they have done 200km without fault..I also get the following random code that I clear but it keeps coming back but can’t seem to get a diagnosis on it

B1D21-13 (2F) Remote control switch
General electrical failure - circuit open

Has anyone got any ideas? I love the car but I can’t trust driving it

[BradC]

This is the codes I got.

P0087-00 (2F) Fuel rail/system pressure
- too low

P2290-00 (6C) Injector control pressure
too low

I had it towed to Land Rover and a few days later they had a look at it and it has run fine, they have done 200km without fault..I also get the following random code that I clear but it keeps coming back but can’t seem to get a diagnosis on it

B1D21-13 (2F) Remote control switch
General electrical failure - circuit open

Has anyone got any ideas? I love the car but I can’t trust driving it

A familiar feeling unfortunately.

The B1D21-13 (2F) is associated with the steering wheel controls. Could be the clockspring or pretty much anything between the wheel and the stereo head unit.

The other two are characteristic of HPFP but can also be LPFP, blocked filter or as pointed out previously a dodgy fuel return line from the filter to the tank. What year is it? EU3 or 4? The original P0191-24 sounds sus. That comes from the sensor on the passenger side fuel rail.

Has anyone done a flow & pressure test on the low pressure fuel system? Jump the relay in the engine bay fuse box and test both flow and pressure at the schrader valve near the HPFP.

Do you have a GAP IID? I found it really illuminating to log/graph the HPFP valves, pressure and throttle position as it faults.

Edit: I also drove it for a day with a fuel pressure gauge cable-tied to the drivers side wiper to rule out the LPFP and Fuel filter. Since you've already done the HPFP it's not "likely" to be that. Was it a brand new one? One member had his replaced with a "good" second hand unit, which turned out not to be and there's plenty of anecdotal evidence of less than satisfactory "refurbs" around.

[Dashing]

A familiar feeling unfortunately.

The B1D21-13 (2F) is associated with the steering wheel controls. Could be the clockspring or pretty much anything between the wheel and the stereo head unit.

The other two are characteristic of HPFP but can also be LPFP, blocked filter or as pointed out previously a dodgy fuel return line from the filter to the tank. What year is it? EU3 or 4? The original P0191-24 sounds sus. That comes from the sensor on the passenger side fuel rail.

Has anyone done a flow & pressure test on the low pressure fuel system? Jump the relay in the engine bay fuse box and test both flow and pressure at the schrader valve near the HPFP.

Do you have a GAP IID? I found it really illuminating to log/graph the HPFP valves, pressure and throttle position as it faults.

Edit: I also drove it for a day with a fuel pressure gauge cable-tied to the drivers side wiper to rule out the LPFP and Fuel filter. Since you've already done the HPFP it's not "likely" to be that. Was it a brand new one? One member had his replaced with a "good" second hand unit, which turned out not to be and there's plenty of anecdotal evidence of less than satisfactory "refurbs" around.

It’s a 2008 EU4 car, the B1D21-13 (2F) fault is a odd one as there is no steering wheel audio controls.
I have a Gap iid tool and have used it a little, it would be good to graph the faults but as it’s so intermittent..Guess it might be a good idea to log/graph record all hpfp related items every time I drive it until it happens again.
As yet I haven’t done a LPFP pressure or flow test but have pressed the schrader valve whilst the pump is priming and there is good flow there. Good idea driving around with the pressure gauge.
The new HPFP I installed was a VDO factory reconditioned unit, both the volume and pressure control valves looked brand new and so did the pump

I have also been wondering if when it goes into limp mode is the low fuel pressure a result of the ECU restricting performance due to another unrelated issue?
I hope to get it back from Landrover tomorrow and I’ll look at replacing the pressure sensor on the fuel rail. I’ve also read that a faulty fuel temperature sensor can give the same fault code as high fuel temperature will tell the hpfp to reduce pressure.
I think I will also replace the brake light switch as everyone seems to replace it although I don’t think that’s the issue, I’ll try anything.
It will be easier to diagnose if it was constantly faulting but hard as it’s so intermittent and unpredictable. Driving style doesn’t seem to make any difference also

[BradC]

If it's any consolation I drove logging every trip for months until it played up. Once it started to become more frequent it was easier to nail.

Given the manufacturer recon pump it's "probably" not that.

I've also had limp mode due to :
- Brake light switch
- Sticky EGR valve
- Faulty DPF differential pressure sensor
- Duff battery

Only the EGR & DPF logged plausible and targeted codes.

Being hopeful I bought a fuel pressure sensor, but that was ruled out by watching the logs to see the sensor output was plausible before I replaced it.

[Eric SDV6SE]

Have you ruled out earth leads? Intermittent faults caused by faulty earth points are not uncommon.

[Dashing]

If it's any consolation I drove logging every trip for months until it played up. Once it started to become more frequent it was easier to nail.

Given the manufacturer recon pump it's "probably" not that.

I've also had limp mode due to :
- Brake light switch
- Sticky EGR valve
- Faulty DPF differential pressure sensor
- Duff battery

Only the EGR & DPF logged plausible and targeted codes.

Being hopeful I bought a fuel pressure sensor, but that was ruled out by watching the logs to see the sensor output was plausible before I replaced it.

Yes I think when I get it back tomorrow I’ll start data logging to help isolate the fault.
I’ll change the brake light switch also..did you get a fault code that directed you to it?
The battery is about 12 month old and it’s got a new alternator but when I start it in the mornings the battery is down to approximately 11.6volts so either it’s being drained from something or the battery needs replacement

[Dashing]

Have you ruled out earth leads? Intermittent faults caused by faulty earth points are not uncommon.

I have removed all the earth leads and points I can find including the one behind the front right side mud guard and all have been clean. I thought the same and was hoping it was that but no success so far

[PerthDisco]

Perhaps unplug all the harness connections behind the battery and give them a clean with electrical spray, check for corrosion and reinstall with a good wiggle. Easy and worth a try.

[Dashing]

Perhaps unplug all the harness connections behind the battery and give them a clean with electrical spray, check for corrosion and reinstall with a good wiggle. Easy and worth a try.

I’ve removed and cleaned them all, no evidence of corrosion and all the wiring into the plugs seems secure, I’ve checked all the other plugs on the engine too and they too seem good

[Bulletman]

You may have tried these but years ago I had random faults that drove me mad, I just cant remember if the codes were what you have.. but anyway my issues were a faulty battery that showed good voltage but once put on a load tester the battery was dodgy, which in the end was a fault with the actual terminal in the battery.
Another set of faults that were real random turned out to be a bad earth connection on the 2 studs on the inner guard just in front of the start battery , they have 2 thin wires going to them .. 1 to each stud. If I remember correctly those faults were something like lost data to transmission or something like that.

Bulletman