HDC light and F4

Nodge68 said:

Just keep an eye on coolant level. The thermostat can leak unseen making short work of the head gaskets.
Also make sure the tyres are all the same make/ type with the least worn on the rear. This will help keep the VCU and IRD in good condition. Lastly enjoy it

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I am "old school". I grew up in the times when checking the tire pressure, oil, coolant, and PS fluid was a weekly routine. I also rotate tires on every oil change. Since I'm running Castrol Edge Titanium in all my vehicles, oil gets changed every 10-12K miles.

Hippo will be a strictly work commuter for my wife (10-12 miles a day), and this amounts to 3K a year! Climate is so mild over here, that the usual "gospel" of changing oil once a year doesn't even apply. The thing is now 12 years old, and doesn't have ANY rust anywhere.

In a week or so, it will go in for a partial paint job. One side has scratches consistent with someone pushing the bicycle next to it, in a tight garage, and the other side has few "shopping cart encounters". And that's about it. No "mods", no frills. Tires have about 100 miles on them (new set of five put on just before the belt junked the motor). I'll strip the parts car of all usable stuff, for future use, and junk the rest. Little Hippo will have a good "retirement home" over here! Since I'll be in it for about the double than it's "worth", it will never be sold (spare engine/tranny waiting!). To me, "worth" is NOT the "market value", but what I get out of it in terms of daily reliability, lack of expenses, and enjoyment in "problem solving", and occasional wrenching (for fun!). "Reliability in Freelander" might sound like an oxymoron, but the thing will never be more than 10 miles from home, we have free towing from AAA, and cell phones at all times. We also have five other cars to use if we "need to". Wife is a physician (writes her own schedule), and I am retired. No dangers to "get stranded", or to be "late" going ANYWHERE.

The most appealing aspect of driving Hippo from my wife's perspective? You can drive all day long in the city, and not run into another Freelander! They are EXTINCT in these parts.

I can't wait to have it all done, and take it down to the junkyard to show it off!

Danielsand said:

I am "old school". I grew up in the times when checking the tire pressure, oil, coolant, and PS fluid was a weekly routine. I also rotate tires on every oil change. Since I'm running Castrol Edge Titanium in all my vehicles, oil gets changed every 10-12K miles.

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I'm the same. Weekly checks is the only way. I think the modern motorist is to used too turning the key and driving and not looking under the bonnet. You wouldn't believe the number of siezed engine's i've seen over the years due to lack of a simple oil level check.

From 1995-2000 I owned two car dealerships (after I got out of the uniform). Had VW, Saab, Subaru, Buick, and Isuzu franchizes. From 2000-2010, I owned two gas stations with full service carwashes/lube. I think I've seen it all.

Knew a guy who took a great pride in saying that he never changed oil in his Expedition, with 169K on the clock!

Since I lived in Europe over 30 years (on and off), I pretty much have European mentality (in more things than just vehicles). In the States EVERYTHING is disposable,.......vehicles, houses, buildings, businesses, marriages,....everything. I grew up with different outlook on life. I buy cars used (2 years minimum!), pay cash, and have no debt to speak off. I like wrenching (never "trained" as a mechanic, but been wrenching all my life). I LOVE restorations (cars, bikes, guns, airplanes).

I don't understand people that don't care about their posessions, or the ones that "have to have" the latest gadget, no matter what it is.

This Hippo "rescue" gave me a great deal of joy.

The only thing ABS related at the rear is the brake lights and the ABS sensors on each wheel. There isn't a reason why a diff mount would fail and cause the F4 problems you've had. the auto/drive is reliant on the ABS to a certain extent. It may be a coincidence your problems are resolved or more likely the garage have done something else. There should have been codes in the auto's computer, or you would hope so as the "system" found a fault and warned about it. They may not want to tell what they did to solve it.

I am sure YOU know about this vehicle more than they do. I am certain.

I drove it from the garage to the ranch on Monday night, with no lights, and no warnings. We decided to leave it parked until the diff mounts arrive. And guess what? I decided to drive it to the carwash today (bored as I am!). After I heard the first "bump" from the differential, amber hippo!, "service engine soon", and F4 appeared.

Instead going to the carwash, I drove straight to the garage (in F4). They SWEAR that Hippo has some kind of protection built in, and when it senses the diff jumping up and down, it goes to "safe mode" to protect itself. They say they need to change the diff mounts, erase the codes, and go from there.
I'll let them. I am anxiously waiting for the mounts to arrive.

Tenacity + stubborness + plenty of "disposable funds" = .......I WILL find the solution to this!

The floppy diff mounts could potentially be sending some kind of erratic pulse to the ABS ECU via the ABS sensors. That's the only connection to any computer at the rear. I do know that the ABS ECU has a rough road routine. This works by monitoring and passing the information back to the engine ECU. The ECU will then know that the driver train is experiencing torsional vibrations. This data is then compared to the crank angle sensor signal so any misfire type faults will be temporarily ignored. The gearbox ECU will also have a similar routine.
This fault could be ABS related because of the failed diff mounts, but not likely.
I do suspect however it's a wiring fault that is showing it's self on larger bumps.
Time will tell once the diff mounts are replaced.

Would the hdc yellow be on just to say HDC is not available - because of the F4 gearbox problem?...something should show to stop you going down a steep hill expecting the HDC to work when obviously it won't...in limp mode...just my thoughts

I may get the hang of this posting one day. Managed to delete the last one. Ere tis again:

Where are the rear ABS sensors located? How does the ABS sensor sense a moving rear diff? The sensor is a fixed coil of wire which picks up the movement of the wheel via the relucter thing. It knows when the wheel is turning but not the direction. It can fail open circuit, short circuit, high resistance (bad contact) or low resistance (damp in it etc). I just can't see a way the ABS sensor can detect the rear diff moving. If this were the case we'd have loads of F4's flashing everywhere.

Be careful about people reflashing your auto gearbox computer. It's been done in the UK before and some still offer the service. Some companies offer it as an upgrade. I only know of 2 people who did it previoulsy. Both scrapped soon after with feked auto.

Can someone tell me where is the Jatco computer located? I was able to find only the engine management computer, and MAYBE, that's what's stopping this car to work properly (maybe I need to swap the tranny computer, if it's separate from the engine comp).
All I know is that this powertrain worked fine in the donor car, and now it doesn't. There is no reason for the tranny to "develop problems" after the swap,......except if the proper communication between the computers can not be established, and/or damaged electrical connections (no evidence of that).
From what I know about the ABS, I tend to agree with all of you (no connection between ABS sensors, and the diff), however.............all systems are so intergated together in the modern cars (and Freelander especially), that some communication might be possible. (ABS computer and tranny computer not talking to the engine, and vice versa) It could also be something as simple, as the shifter switch being confused (all gears are indicated properly).
Computer guy said that his program can "see" if any electrical connections are broken, and exactly which one. He did not find anything amiss.
I'll replace the diff mounts on Monday, and start over.

What I need now, is the exact location of the ABS computer, and the transmission control computer. These DID NOT follow the powertrain from the donor car, and MAYBE they are not communicating with the engine management. That's the only thing I can come up with.

Hippo said:

I may get the hang of this posting one day. Managed to delete the last one. Ere tis again:

Where are the rear ABS sensors located? How does the ABS sensor sense a moving rear diff? The sensor is a fixed coil of wire which picks up the movement of the wheel via the relucter thing. It knows when the wheel is turning but not the direction. It can fail open circuit, short circuit, high resistance (bad contact) or low resistance (damp in it etc). I just can't see a way the ABS sensor can detect the rear diff moving. If this were the case we'd have loads of F4's flashing everywhere.

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The ABS sensors and rings are mounted on the stub axle at the hubs. The sensor produces a small electric pulse every time a tooth of the ring passes the sensor. The ABS ECU measures the speed and spacing of the pulses. Much like morse code. So it would read like ---------- while driving on a flat surface. But if the wheel runs through a pot hole large enough for the wheel to loose contact with the ground, the ECU would see something like this ---..-...--- This would be interpreted as a rough road and signal the other ECUs that where might be some strange feedback from other sensors too. These would normally be ignored temporarily.
A very loose diff could also trigger these ABS sensor pulses as it is joined to the hub by the drive shafts. The sensors and ECU are very sensitive bits of kit. Think of it as braille for the car's computer literally reading the road.

Danielsand said:

Can someone tell me where is the Jatco computer located? I was able to find only the engine management computer, and MAYBE, that's what's stopping this car to work properly (maybe I need to swap the tranny computer, if it's separate from the engine comp).
All I know is that this powertrain worked fine in the donor car, and now it doesn't. There is no reason for the tranny to "develop problems" after the swap,......except if the proper communication between the computers can not be established, and/or damaged electrical connections (no evidence of that).
From what I know about the ABS, I tend to agree with all of you (no connection between ABS sensors, and the diff), however.............all systems are so intergated together in the modern cars (and Freelander especially), that some communication might be possible. (ABS computer and tranny computer not talking to the engine, and vice versa) It could also be something as simple, as the shifter switch being confused (all gears are indicated properly).
Computer guy said that his program can "see" if any electrical connections are broken, and exactly which one. He did not find anything amiss.
I'll replace the diff mounts on Monday, and start over.

What I need now, is the exact location of the ABS computer, and the transmission control computer. These DID NOT follow the powertrain from the donor car, and MAYBE they are not communicating with the engine management. That's the only thing I can come up with.

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TCU is in the ECU box by the battery. The ABS ECU is under a seat iirc.

Thank you.

Nodge68 said:

The ABS sensors and rings are mounted on the stub axle at the hubs. The sensor produces a small electric pulse every time a tooth of the ring passes the sensor. The ABS ECU measures the speed and spacing of the pulses. Much like morse code. So it would read like ---------- while driving on a flat surface. But if the wheel runs through a pot hole large enough for the wheel to loose contact with the ground, the ECU would see something like this ---..-...--- This would be interpreted as a rough road and signal the other ECUs that where might be some strange feedback from other sensors too. These would normally be ignored temporarily.
A very loose diff could also trigger these ABS sensor pulses as it is joined to the hub by the drive shafts. The sensors and ECU are very sensitive bits of kit. Think of it as braille for the car's computer literally reading the road.

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I was taking the ****. May not have come across well. I appreciate where they are and what they do, but there's no way the ABS can sense diff movement. If it were able to sense movement it would cause havoc oft road. Especially axle twisters. The worst that can happen is the diff case rotates on the driveshaft axis (won't turn much) and that still won't trigger the OP's fault. With the fault being intermittent and so many things being played with it's going to be difficult to relate it to one thing. Similar to my intermittent problems.

Auto's computer is next to the engine computer. It's the one with the smaller connector. Larger one is the engine computer. Both in the L shaped plastic box under the bonnet.

ABS computer is part of the modulator thing under the bonnet and sit's at the front of it, behind the headlight side.

Computers under the drivers seat are the cruise control.


P8171537 DcCoutT

Hippo said:

Auto's computer is next to the engine computer. It's the one with the smaller connector. Larger one is the engine computer. Both in the L shaped plastic box under the bonnet.

ABS computer is part of the modulator thing under the bonnet and sit's at the front of it, behind the headlight side.

Computers under the drivers seat are the cruise control.

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I found your post on Youtube, and followed it to the letter (thank you). ALL sensors, and all solenoids are within the specified range! So (I'm guessing) cleaning the barrels, and the multipin connectors is not needed (they seem to all be operational). So now what?

Testing the resistance can only atest the continuity, but my "low clutch solenoid" could still be sticking. Since this setup (engine AND tranny) worked FINE in the donor car, I don't think I have a sticky solenoid. All this is FRUSTRATING, and I wish someone could chime in that had the same problem. I know you did (found your old post about this), but yours was a simple problem of WD40 in the barrels.

I'll replace the diff mounts, spray some contact cleaner on all connectors, and clear the codes. We'll see. There is no way I can give this to the LR dealer! They WILL charge about the same as the car is "worth" in the good running condition.

The only thing that did not come over from the donor car, is the ABS control unit (tranny computer was swapped yesterday, with no changes), but according to the computer guy that had a "stab at it", it works fine.

I am totally confused, and wish that I was born about 50 years earlier,.....points, distributors, and carburators. Easy, peasy. Computers took over, and now we're all up the ****ecreek! Most of the systems in the cars of today, are made ON PURPOSE to break down as soon as the vehicle is out of warranty, and to PREVENT DIY as much as possible. Then you have parts that are "dealer only", and the list goes on.

We are all being bled dry. They get you coming and going.

I bought a hawkeye so I could get a bit further with faults. Knowing the fault code is amazing compared to starring at it. I was messing with mine and it suddenly wouldn't start. Starter motor would run ok. I was away from home and thinking of calling the AA. Had me hawkeye with me so looked at the codes and it said P1666. I cleared this but still wouldn't start. Engine shows as immobilised changing to mobilised. Key was detected... I was able to see the code was "security code not received". in the end I disconnected the battery then connected it again. Started first time. A lucky guess with a bit of logic. If it were not for that I would have had to call the AA.

I've learnt so much from me hawkeye it's a case I wouldn't want to buy another vehicle without first checking out what diagnostics are available. Hawkeye is expensive but compare this to requiring diagnostic at a garage. Also the need to carry it there if it won't start.

If you clean the barrel connectors use electrical contact cleaner. WD40 displaces water but leaves a greasy film. I tried some special connector stuff which you put in to stop ingresses of muck etc but that just created bad connections between connectors/pins. The first time it changed from 3rd to 4th it lost drive and selected 4th and flashed F then 4. I had to clean the connectors as best I could and opened then push together many time to clear some of the grease. It then worked ok so got it the short distance home and cleaner the barrel connectors proper.

I recently cleared an srs red light on the dash for someone. I've done this before for a member on ere. too.

I need some thought on this: If one checks resistance on the barrel, and it comes within specs, that indicates the solenoids to be OK (but doesn't tell you if they are sticking). Also,....if you check there, you can't "see" if the barrels need cleaning (in case some contacts are dirty). Right?

But,.....if one checks the resistance at the tranny computer box (with barrels connected), and the resistance is within the specs, it means that the continuity is established through the barrels (no loss of contact, no cleaning, no zip ties needed), right?

Since I checked both ways, and got the good readings, I think I can eliminate barrel connectors issue,....or am I missing something?

The connectors need to have a solid connection, even with the engine vibrations and movement. It's amazing just how much the engine/ transmission assembly moves about while in motion.
With intermittent faults, connectors would be my first port of call.

All is good!

And I am still not sure what it was. In short,.......I sprayed the shiite out of the barrel connectors with the contact cleaner (thank you all who pointed to this), I had the battery on the charger at 2 amp overnight (reading 12,4V before the charge, and 13,6 this morning), the guy changed the diff mounts, and.......drumroll,.......no warnings, no F4, no issues! Like nothing happened. I didn't even have to clear the codes,....it all disappeared.
Hippo drives happily, shifts like a dream, and wife is HAPPY. If she's happy, I'm sure I'll be VERY happy very soon!

I want to thank you all for coaching me on this, and I thank you all for your time, and knowledge. I'll stick around, read, and post IF I have anything to contribute. This little car is still a puzzle for me, but I am determined to get under its skin.

Next week Hippo is going for a "facelift", and it will be a happy little critter again. Wife thinks of it as a "pet", and it will be treated as such.

Thank you again.

Glad you are sorted. This white contact grease appears to harden with age. It causes similar intermittent faults on the light switchs and ignition switchs on all Rover products.
One again, glad you are sorted