L322 Petrol. Idle / Viscous fan issues at engine start

When accelerating you hear the engine in what appears to be in a reduced engine performance joined with a loud and increasing engine fan noise as it travels through the gears. I know these are the symptoms of the terminal circuit high/ Viscous fan over speed and protecting the engine as the ecu is controlling the fan due to a fault. Identifying the fault is another thing. Speaking to a mate / technical diagnostics engineer for Volvo stated that they constantly have to refer to head office technical to identify parts to try but would be lovely if we had endless supply of parts to keep on trying before eventually getting the right one.

If the engine is in limp I would expect more faults , what JLR engine is it ?

It the 4.4ltr v8 jaguar engine. Yes the GAP is a very good piece of equipment. Tried the sdd but doesn’t work well when battery is below 12.5v and need good power source before you can do anything and only get one day usage. GAP gives a lot of vehicle options. I cleared the codes and they come straight back.

The fan that is running is the AC fan rather than the viscous fan do you think , the electrical fan in front of the rad?
I wonder if it’s worth pulling g the HEVAC fuses to see if stops the fault ?

I think you are correct,It’s the large fan behind the radiator that’s rapidly spinning the minute the engine kicks in and the battery indicator illuminated the minute the fan starts but jlr sdd refers to the Viscous fan being a possible fault for the Generator field terminal - circuit high error.
I’ll try disconnecting the hvac fuse tomorrow and see if this makes a difference. Thanks for all your help

If you have an electric fan in front of the aircon condenser rad then they have been known to catch fire as the internal windings short out . The 2006 TD6 I nursed for a while tried it while I was trying to resolve a non start issue and I crapped myself when smoke poured out the front grille .

Well I pulled the hevac fuses (take them to be A/C fuses) and didn’t resolve the problem unfortunately. Pulled the wing mirror heater and when fuse reinstalled and errors cleared and checked got rid of that. Noticed a large 50amp fuse not mentioned in manual but shown on fuse cabin flap to have a black fan. Tested and it didn’t make any different, not actually sure what that is as the manual has quite a few different fuses to the fuse box flap

Just to update ....Battery charged to 12.8v and charging at 14.5 v when engine started.Tested the hevac a/c fuse and this appears to be drain on battery. When ingnition off and fuse in - drain reading settles at 1.9 amp , pulled fuse out 0.5amp.
Still 1100rpm at engine start and a lot of fan noise ...battery indicator still on.

If the battery indicator is on then I think you are looking at an alternator fault as per @Datatek post #10, try disconnecting the alternator to see if you lose any drain.
Do you have a large multi plug to the left of the radiator when you look at it that is the power and trigger wire for the AC fan, if so, you could try unplugging that to see if that does anything.
I think even 0.5 amp is still too high drain but there may have been other systems still shutting down.
The high RPM i believe is still the low battery or the system thinking it has a low battery so it raises the rpm at idle.

Unsure whether this makes sense to you but after charging the battery again 12.8v I tested the drain. The drain was around 2.1amp so removed the ac fuse and drain went to 0.5 but internal lights and glove box light were on so closed and went down 0.1.
Looked at the battery voltage ant this was now 10.5volts so charged it again. Back to 12.8v which stayed stable until cleared codes and started engine. Fault with fan/ idle speed still present. Turned off engine and monitored drain. Hung around 9 amps for 1-2 mins then down to 0.2 but battery voltage back to 10.5 volts.
I tried alternator diode test across battery terminal on ac voltage test on meter and get 0.1. Not sure whether this is sufficient to drain battery in such a short time.
I pulled the fuse on the alternator and did check also with fully charged battery and seems to react the same with similar figures.

Yes your right the alternator problem seems the most likely cause of the increase fan and rpm speed and battery indicator. Possibly with hevac issue also.

There are others with far greater knowledge than me on the electrics , I tend to follow a methodical approach to trace them even though I may not understand why they have a fault.
10.5 volts is a very flat battery, I have an optimate 6 that runs various tests to try and salvage batteries I have an old battery off the TD6 I was messing that I replaced the battery on for a great Superbatt one that is brilliant for about £65. Anyway the old battery after a full charge would just about start the car once or twice and would not start the car after a day of being parked but would still read 12.6 volts or around that. I fully charged it overnight on the optimate to try and jump my 4.4 and it didn’t even allow one crank.
Your battery light concerns me, in my mind that points to alternator especially if it’s the same with other batteries. Either that or you have a short.
Try unplugging the fan like I said .

Keep the faith !

This site and you have inspired me not to give up. Thanks. I’ll try disconnecting the fan and see what happens. Those optimates are good, have one for the Hayabusa over the winter period. I’ll pop along for free battery check to Halfords and take the 5 year warranty up as I think the battery may have spent too long below the 10.5 v Mark for too long.

The optimates are excellent for keeping a battery alive, my ZX7R battery lasted 10 years compared to about 4 months when it was not being used but I’ve yet to successfully rescue a deep discharged or sulphate battery using one.
Hope you get it sorted.

Thanks. Any ideas on how to get some electrical techs involved. The alternator and battery was tested and are fine. Diodes are doing what they should. I pulled the cable to the fan housing as suggested and although it didn’t reduce the rpms the fan spun in what sounded like a normal conditions.That was the large black blades and the small metal centre. Error came up on fan 1 on the diagnostics and cleared the minute the cable was reconnected. But the minute it was reconnected sounded like it was ready to take off. What I still can’t undestand is the battery within seconds starts to head down to 9.7volts the minute you stop the engine. Charge the battery up and it maintains 12.8volts

The only thing i can suggest is to try and find the source of the battery drain, all those volts are going somewhere and sounds like a short to me but then I am only guessing.
The Generator field terminal high has got to be a clue somewhere and I still think is pointing to alternator, high means too much voltage so wondering if there is a regulator fault.

Have you checked all your fuses after replacing the FSR.

Could the FSR be faulty, is it easy to remove ?


bit of info here
https://www.obd-codes.com/p0626

Have read here, different vehicle but similar problem, resolved on page 3 i think.

https://www.aulro.com/afvb/l319-dis...codes.html?s=a9cdc9f89f40c40c43581a5bb8f8ce7e

My thoughts were to put the old one back in and see what happens. Reading about the generator field issue it includes many modules “most likely cause of this code being stored is a defective generator or generator control module. Many generator control circuits are integrated into the PCM. Other causes may include corroded, open, or shorted wiring or connectors in the CAN Bus harness, a loose control module ground strap or broken ground wire, the CAN bus may also be defective.” problem is I’m not sure how to test and clearly just pulling fuses is not identifying or suggesting what might be wrong. The drain hangs at 9amp on the negative side and then after a minute or so drops to 0.1 -0.2 but it’s that minute at 9amp which can only be hammering the battery unless I doing it wrong, a fluke clamp meter around the negative.
I’ll check out your posts thanks. Might just stick to bikes after this. What we do to try and save some money.

Interesting post. I would blame the wife for going shopping.

It's getting close to auto electrician time , either that or the AA man..