Lr3 tdv6 low fuel pressure / limp mode

Hi all

i recently picked up a 54 plate lr3 tdv6 with a manual box as a cheap tow truck. I finally got around to towing our trailer and have a few issues.

when under load and around 3k rpm it throws up and engine fault and turns off special programs but not warning lights come on. I’ve been scouring the net and soaking up as much knowledge as possible. These are the codes I got when reading with an icarsoft v2.


U0401 - invalid data received from engine control module / power train control module
B1b02 - low frequency coil
B1b69 - 12 volt supply circuit
B1b70 - local interconnection network bus circuit 2
B1c26 - pedal motor feedback circuit
P2290 - injector control pressure too low
P0087 fuel rail / system pressure too low

I started by changing the brake bulbs and brake pedal switch as I read this can throw up the special programs turned off. I then went onto change the fuel filter for a genuine lr one. (old one did feel heavy)
All turbo pipes have been checked for splits and seem fine so I began to look a little deeper. I started by testing the amps on fuse 1 results are below.

3.8a with ignition on and engine warm from a run.
4.2a while engine running at 2k rpm.
I bridges the relay for the pump and measured how much fuel it would throw out in a minute and I’m looking at 1L plus. I’ve tested the fuel pressure on the valve on top of the engine with the only gauge I had and it’s looking around 6psi could be a little more but it does throw plenty of fuel out.

my next step was going to be dropping the tank and looking at the lpfp but I’m leaning towards the high pressure pump being the culprit. Any input and advice welcome on what else I can try before I start emptying my pocket on a hpfp.

I suspect the low pressure fuel pump is at fault.
A healthy LP pump should draw about 10 Amps, so drawing 4 Amps suggests it's on its last legs.
There should also be over 20 PSI of pump pressure, 6 PSI is too low, and another pointer to a faulty LP pump.

Nodge68 said:

I suspect the low pressure fuel pump is at fault.
A healthy LP pump should draw about 10 Amps, so drawing 4 Amps suggests it's on its last legs.
There should also be over 20 PSI of pump pressure, 6 PSI is too low, and another pointer to a faulty LP pump.

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Hi Nodge thanks for the reply, I thought around 7 psi was a good pressure I must have got the wrong info from another forum. Looks like I will be dropping the tank and inspecting the pump do you know of anywhere that supplies the pumps I’ve read a lot of people have brought cheaper prices ones and they’ve been faulty. Again thanks for the quick reply and advice.