Quote:

Default (Limp Home) Mode

If a transmission fault is detected by the TCM, the TCM adopts a limp home mode strategy. 'TRANS. FAILSAFE' is displayed in the message centre and, if the fault has an effect on engine emissions, the MIL will also be illuminated.

In default mode, P, R and N functions operate normally (if the fault allows these selections) and the TCM locks the transmission in 3rd or 5th gear to allow the driver to take the vehicle to the nearest dealer. The torque converter lock-up clutch is disabled and reverse lock-out will not function.

If the vehicle is stopped and subsequently restarted in the default mode condition, the TCM operates normally until the fault which caused the condition is detected again.

When limp home mode is active, the gear position indicator will show one of the following letters which defines the fault type:

'F' - transmission is operating in limp home mode
'H' - transmission has reached overheat threshold temperature and transmission is operating in limp home mode
'E' - CAN bus is off and transmission is operating in limp home mode.

If electrical power is lost and the transmission is operating in mechanical limp home mode, the selector lever will not be locked in the 'N' position by the shift interlock solenoid. The lever will be locked in the 'P' position and can only be released by using the interlock emergency release lever or by correcting the electrical fault.

What this doesn't explain, however, is that faults elsewhere can also cause the transmission to go into limp mode. Naturally, there are extensive communications between the transmission and engine.

 Current: Discovery 3 06MY (55 reg) HSE Auto Zambezi Silver Allisport Fast Road Intercooler, V8 Brakes, Silicone IC Hoses, EGRs Blanked, Remapped, De-Cat pipe, FBHIC
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Disco_Mikey wrote:

Incorrect gear ratios are a little worrying, but it may be as simple as a worn torque converter

Having done some reading after replacing my own gearbox, incorrect ratio faults can be caused by worn TC lock up clutch worn, or pressure loss, either caused by a worn TC, or pressure loss in the valve block

Hi Mike
Thanks for getting back in touch so quick, I really appreciate it! When I saw those codes saying that my heart sank but nephew said that it seems like it might have had a problem years ago, which was most probably repaired, I don't know....that could be why historical was recorded!? It has never shown a problem ever with us since we have had it (about 4000 miles approx.) (spoke to my wifes mate who was the last owner and said it has never had a problem at all), seems that the N/S EGR is not functioning anyway. He did say that while he has spent a lot of money servicing, cambelts, brakes and so on, he doesn't think the oil in the gearbox has ever been done or the gearbox filter itself. could this be anything towards it? I could probably drive 30miles or so at normal speed and it would be ok but if I upped the speed and load it would probably show the fault, the ironical thing is that if I turn the engine off and restart it all is well again, I'm still trying to look on the bright side and not a gearbox. (see your PM)
speak to you again soon
best regards
Bryn

Lost for Words wrote:

Hi Bryn,

What mileage are you at - sorry, this was what I meant when I asked before (Bryn sent me a PM, BTW, for any confused onlookers!)?

What voltage is the alternator outputting?

I'm afraid a genuine gearbox issue (of some kind) is now looking probable. Have you had any judder at all?

blackleyhurst wrote:

My D3 was doing this especially on hills when towing caravan, it happened over a three year period. The main agents claimed they could not find a any faults. Gave up and took it to local independent who plugged is diagnostic computer in, walked into his office came out with a printout and said the turbo charger was the problem. It cost me £1500. I've worked it hard for the past six months without any problems.