Freelander 1 Freelander TD4 2004 Low Fuel Pressure

Hi guys and thanks in advance for any advice given.

Ran my freelander last week for a few miles and the engine started throwing me all over the place with the yellow engine light flashing on and off (turning limp mode on when it was displayed). Drove it home and since then when I start it up it struggles. The revs dip initially then get up to the normal revs whilst idling. But the revs will still dip very slightly and won't remain constant like normal.

Even when the engine light and limp mode are not on I can still feel the engine is skipping and pulling. A few months ago I did put petrol in the tank and ran it a mile before I had it pumped out. Since that disastrous event, I've run it about 600 miles. I replaced the fuel filter a few days ago thinking this would cure the problem but it made no difference. I have noticed the engine isn't quite getting up to temperature as it did a few weeks ago but perhaps this is just the cooler weather.

My next step is to buy a harness assembly for the fuel pressure sensor (YMQ503320) to rule out electrical fault but would like advice before throwing more money at it.

If it were mine, I'd get the diagnostic codes read to find out why the EML is being lit.

GrumpyGel said:

If it were mine, I'd get the diagnostic codes read to find out why the EML is being lit.

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Thanks. Forgot to add the EML is due to low fuel pressure.

Low fuel pressure where ? low pressure or high pressure sensor ?

Oldyam said:

Low fuel pressure where ? low pressure or high pressure sensor ?

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I'm not sure, garage just told me low fuel pressure. I will ring tomorrow to find out.

Most likely the low pressure fuel pump or filter.

Nodge68 said:

Most likely the low pressure fuel pump or filter.

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Do you think I should look at replacing the pump given i've already done the filter or should I look at the sensor first?

Really you need to get the fault code, so you can identify exactly what's up with it. I only suggested the LP pump, because that's a common cause of low power and ! light.

Nodge68 said:

Really you need to get the fault code, so you can identify exactly what's up with it. I only suggested the LP pump, because that's a common cause of low power and ! light.

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Ok no worries. Will get the code and get back to you. Cheers.

Nodge68 said:

Really you need to get the fault code, so you can identify exactly what's up with it. I only suggested the LP pump, because that's a common cause of low power and ! light.

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Alright. The fault code is P0139 - fuel rail pressure sensor malfunction. Started it up cold today at it was okay until it heated up. ! light only seems to kick in once the engine is up to or near temp.

That being the case, the harness is probably the place to start, maybe the sensor itself.

You could try cleaning up the connector before replacing bits, even if it only makes things better for a short while, you know its the issue before splashing the cash.

For when you do the harness hers the TDB and instructions

https://www.landyzone.co.uk/land-rover/freelander-td4-fuel-rail-pressure-sensor-harness-tsb.307429/

LUKBENPHI said:

For when you do the harness hers the TDB and instructions

https://www.landyzone.co.uk/land-rover/freelander-td4-fuel-rail-pressure-sensor-harness-tsb.307429/

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Thanks for that. I'll clean the connectors to make sure it is that then i'll look at buying the harness.

Ok...I've cleaned the connectors with contact cleaner and a tooth brush. Though I tried my best, they are still pretty dirty:





I could try with a wire brush because the dirt is a tough but i'm afraid of wrecking the connector. Based on these photos, is it likely that this is the problem? I took it for a drive after cleaning the connectors and the engine light (and limp mode) came up once it was driven for a few miles and had the chance to heat up a bit. I would note that it started very easily in comparison to the past few months that I have had the car (normally struggles a bit to start and not always first time).

normally problems is in the harness not the connector due to way it runs round engine bay and heat cycles

LUKBENPHI said:

normally problems is in the harness not the connector due to way it runs round engine bay and heat cycles

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Ah ok, excuse my ignorance. I will get a replacement then. Thanks for your help.

cbfks said:

Ah ok, excuse my ignorance. I will get a replacement then. Thanks for your help.

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No worries glad to help woerth checking connector anyway as you never know

LUKBENPHI said:

No worries glad to help woerth checking connector anyway as you never know

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Replaced the harness myself. Started it up and now i've got 2 yellow engine lights, one normal and one !. Still the same problem where the engine is hesitating. Not sure what to do...might replace the sensor next or take to a garage...

normally the sensor and wiring come as a kit or the one I did was so id try sensor first then read the codes

I'd make sure you've got the connections to the EDC in the correct places.