Freelander Diesel Check Engine Light

[101RRS]

My L series freelander diesel has a check engine light that comes on at startup when the engine is warm - does not come on on cold start up.

A few weeks back I towed a series 1 back home - 300km - no issues and the freelander towed at around 100kph in fourth and sometimes fifth when going down hill.

The next day on warm start up the check engine light came on. On cold start it is not on until the next warm start. Last year I had the same problem - was the water temp sensor - replaced it but check engine lite was still there but was all OK when ECU codes were cleared.

This time the symptoms were exactly the same so I replaced the water temp sensor ($20) and took the car in to have the codes cleared this morning.

Codes indicate there is a current fault when hot (intermittant when cold) with the fuel cutoff system in the injector fuel pump but doesn't actually say what the issue is. Could be the signal from the brakes is faulty (reduces fuelling when the brakes are applied), the fuel cutoff solenoid could be faulty but I don't think this has a direct feed back to the ECU - but could be done via other sensors that indicate the engine is being fuelled despite the ECU wanting to reduce. The RAVE highlights all the sensors and what they do but just indicate that the check engine light comes on and if a major fault the fuel cut-off solenoid activates to shut down the engine. If a semi -major fault the ECU turns on the check engine light and runs on a default setting for the faulty sensor so the engine runs on slightly reduced power - minor intermitant faults are only recorded in the ECU - nothing else.

The car runs fine - just down a little on power going up steep hills. To track the problem down will require investigation - diconnecting parts and checking them one by one - could be fixed quickly or painfully slowly - with the associated charges $$$$$$$. I need the car next week so I did not leave it for repair.

So - any thoughts. I am happy to replace sensors but the ECU still makes the check engine light to come on even if fixed until codes are cleared - why they did not design these things so that the driver could press a button the clear codes - and if they continue after being cleared another light "call repairman" comes on.

Thanks

Garry

[101RRS]

I guess that has everyone stumped - or my likely few L series owners on AULRO

Garry

[camel_landy]

Hi Gary,

As you say, go through & check all the obvious bits and make sure all of the electrical terminals are clean.

You say that it runs ine but down on power when under load... Have you had a look at the EGR valve? Could that be stuck??

Also check the air filter & hoses. Could they be clogged or starting to collapse?

That's where I'd start...

M

[101RRS]

Hi Gary,

As you say, go through & check all the obvious bits and make sure all of the electrical terminals are clean.

You say that it runs ine but down on power when under load... Have you had a look at the EGR valve? Could that be stuck??

Also check the air filter & hoses. Could they be clogged or starting to collapse?

That's where I'd start...

M

Thanks Mark - I thought you would be along.

I am happy to check the sensors one by one but without a testbook I cannot tell if the things are fixed or not - I am considering buying a reader - I would prefer a Scan Gauge II because it has a whole lot of other functions but they have really gone up in price lately.

I know I am preaching to the converted - but the reason it is down on power is because when there is a problem with sensor or a sensor reading the ECU switches to a preprogrammed default setting. According to the Rave this is normal for the L series.

However, that said I you thoughts on the EGR valve and hoses and filters are good ones and I will go through that this weekend.

The testbook did say that the problem was related to the fuel shutoff system in the injection pump so I will have a good look as this as well.

The problem is that you can fix things but the error code remains and makes the light stay on until the error code is clear - youn would think the ECU would know things have been fixed.

Thanks Mark

Helpful as always

Garry

[camel_landy]

However, that said I you thoughts on the EGR valve and hoses and filters are good ones and I will go through that this weekend.

I've not really fiddled much with the Freebee system but I have had a look at a couple of other diesel cars of a similar era. One in particular that stands out was a VW where the inlet hose was starting to collapse on full load. The air flow meter would sense the loss of throughput and would immediately put the engine into a limp/low-power mode... Hence the suggestion.

Testbook... Hmmm, that reminds me. I must talk to my neighbour. I found out the other day that he used to own the company that produces Testbook for Landrover.

M

[101RRS]

Ok - drove to Melbourne and back yesterday - 1600km round trip in one day.

On cold start in Canberra - no issues - no check engine light - drove 720km non stop on one tank to Melbourne towing a box trailer - full power available - cruised at 110kph - no check engine light. Engine not turned off the entire trip.

Refulled a hot car in Dandenong - 55 litres. On restart - igntion on - no check engine light - crank engine - no check engine light - engine fires check light come on.

On the trip back home, as the engine was always hot, the check engine light stayed on and the ECU was in limp mode - of my 73kw available - felt like I was only getting about half available power - fuel consumption stayed good though.

So the scenarios:

1. Cold start, air temp below about 20 - no check engine light (check engine light does not come while engine is running) - engine has full power.

2. Cold start but air temp is above 20 - no check engine light on ignition on but it comes on when the engine fires - lite stays on - decreased power.

3. Hot engine and hot air temp - no check engine light on ignition on but comes on when the engine fires - light stays on - decreased power.

This is clearly related to temperature - the last time this happened I replaced the water temperature sensor and was all OK - I have replaced it again but this time but no fix.

I have had it on the testbook - no temperature issues raised - however it does show an issue associated with fuel shut off. This cannot be right as the check engine light does not come at all when the car starts normally - even after driving 700km at 110kph, towing a trailer at temps around 30 degrees C. During this trip - there would have been plenty of times the fuel shut-off system operated - each time I touched the brakes.

The testbook did not identify a faulty sensor but when all faults have been cleared from the ECU, is shows there is no fault when ignition is turned on, and the fault only shows when a warmed (or outside temp is high) engine is fired.

Any additional thoughts?

Thanks

Garry

[camel_landy]

???????

Confused... You will be!

Just thinking through what might be different on a warm start and the only thing that comes to mind are the glow plugs. I don't think there's anything clever going on there but it's a possibility???

If I remember, I'll ping an e-mail over to one of the guys I know in the Technical Academy to see how much he knows about the early Freebees. Don't hold your breath though... It would have been a ling time since he would have worked on one of these!!!

M

[101RRS]

Yes all so confusing and the kit that is supposed to sort this - the testbook - is no help.

Looks like it is time to spend the $$$ and get someone to fix it.

Garry

[TyGras]

I am no mechanic but I am an electronics technician. There might be a sensor that isnt registering a fault after it is hot till it gets a reset from the engine shutting off. This could trigger it to say oh I am hot or something and then the fault dignal is sent. To me if it was just a defective sensor it would trigger when it got hot. This to me sounds like an actual defect but the sensor has a heat issue and needs the ignition to be reset to register it.

My 2 cents worth... either a faulty sensor or a faulty sensor that is also detecting a real issue.

Good luck....

[camel_landy]

Yep, I'm with you on that one (Electronics & Electrical engineer by training here...). The problem comes with knowing how the ECU processes the information to give you the result. With that information, you can reverse engineer and work out which are the likely suspects...

I've e-mailed my mate so hopefully he might have an insight into how the info will be processed.

M

I am no mechanic but I am an electronics technician. There might be a sensor that isnt registering a fault after it is hot till it gets a reset from the engine shutting off. This could trigger it to say oh I am hot or something and then the fault dignal is sent. To me if it was just a defective sensor it would trigger when it got hot. This to me sounds like an actual defect but the sensor has a heat issue and needs the ignition to be reset to register it.

My 2 cents worth... either a faulty sensor or a faulty sensor that is also detecting a real issue.

Good luck....