Gearbox Fault on Dash

My 4.0 1996 Rangie has the gearbox fault on dash,she's done 79600 miles N reg,on reading some posts on here I got a mate with me to do a battery and alternator check,your coments and suggestions will me most welcome

Battery: Engine off.....12.88V

Battery: Engine at 200O rpm..... 14.05V

Battery: Engine at 2000rpm lights,heater,brake lights on .....13.65

Alternator:Engine running.....14.19v 164 mv(drop)

Battery EARTH ..... .28MV

The battery is a 'Lion
brand 70AH 540CCA.

The gearbox is in limp mode 3rd gear,and reverse .....how do I get it sorted peeps?

Had the same problem with the missus disco, turned out to be a fault in the gearbox wiring loom.

Those readings look low to me....maybe thats the problem....P38's hate low volts

Voltages look ok to me, diagnostics needed. Look at gearbox trouble shooting in RAVE for an insight into limp mode reasons. Low volts will give spurious messages but rarely an actual fault.

Drives in D only 3rd gear got reverse too no kickdown either very puzzled

Snowdon said:

Drives in D only 3rd gear got reverse too no kickdown either very puzzled

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See my last post do as it says and your puzzlement may end.

Snowdon said:

My 4.0 1996 Rangie has the gearbox fault on dash,she's done 79600 miles N reg,on reading some posts on here I got a mate with me to do a battery and alternator check,your coments and suggestions will me most welcome

Battery: Engine off.....12.88V

Battery: Engine at 200O rpm..... 14.05V

Battery: Engine at 2000rpm lights,heater,brake lights on .....13.65

Alternator:Engine running.....14.19v 164 mv(drop)

Battery EARTH ..... .28MV

The battery is a 'Lion
brand 70AH 540CCA.

The gearbox is in limp mode 3rd gear,and reverse .....how do I get it sorted peeps?

Click to expand...

Big difference between the alternator measurement and the measurement at the battery, should be no more than 0.1 volt under any conditions. I'd look at the earth strap from the engine to chassis, the connections on the battery, fuse box and starter motor and also look for corrosion inside to plastic sleeve of the positive cables. Use a jump lead fron the alernator to the battery and to earth ect and see which one most affects the volt drop. Ideally you should see 14.2 volts at the battery at 2K rpm.

Most appreciative for all input on my problem 'gearbox fault',Today I tried the jump lead from alternator to +ive battery and then tried the -ive no change or drop whatsoever. The highest reading was 13,85 with lights and wipers on...where's my 14.4,I am determined to get a 14,2 14,4 ....will keep on trying different things as I read more post and take onboard all advice...

one thing I noticed today the vaccum pipe was split in the cruise control,repaired that and sat down and thought.... an uprated alternator 120amps? first see what happens,then a bigger powerfull battery this one looks small plenty of space to take a bigger jobbie methinks........tomorrow's another day...

Snowdon said:

Most appreciative for all input on my problem 'gearbox fault',Today I tried the jump lead from alternator to +ive battery and then tried the -ive no change or drop whatsoever. The highest reading was 13,85 with lights and wipers on...where's my 14.4,I am determined to get a 14,2 14,4 ....will keep on trying different things as I read more post and take onboard all advice...

one thing I noticed today the vaccum pipe was split in the cruise control,repaired that and sat down and thought.... an uprated alternator 120amps? first see what happens,then a bigger powerfull battery this one looks small plenty of space to take a bigger jobbie methinks........tomorrow's another day...

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Biggest battery is an Alphaline 1000CCA 135AH from battery megastore on line, about £98 delivered
You will only see 14.4 volts from the later 150 amp alternator, 14.2 is normal and adequate. A new alternator regulator, brushes and diode pack with a skim of the slip rings is not expensive.

Left it with the local Landrovers specialists yesterday, non maindealers! Their computer would not talk with mine so they are trying a different gearbox ecu next time and take it from there, will keep you posted.

Snowdon said:

Left it with the local Landrovers specialists yesterday, non maindealers! Their computer would not talk with mine so they are trying a different gearbox ecu next time and take it from there, will keep you posted.

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Gearbox ECU is pretty bomb proof. .

First of all sincere thanks for all the replies to my problem you all have been awsome in guiding me to sort the problem out.
As the 'gearbox ECU' came up in the conversation at the garage where I took it to sort out,I being nosey wanted to look for it and to check out it's habitat within the P38was it faulty? was it burnt out?...........it has a very secure place under the passager seat I found out tonight and I am PROUD to say I have now 1,2,3, and a working Sport mode switch along with gear choice display on the dash.......

All it was that the connector going into the ECU was not secured in with the press down clip horizontal holding it in place!!!!!!!!!!!!

This took 5 minutes!!!!!!!!!!!!

Lesson here is... check the obvious first,and to look before you leap!Will be informing the local Landrover garage tomorrow,how did they not see this baffles me to be honest.

Woo hoo :clap2:

Snowdon said:

All it was that the connector going into the ECU was not secured in with the press down clip horizontal holding it in place!!!!!!!!!!!!

This took 5 minutes!!!!!!!!!!!!

Lesson here is... check the obvious first,and to look before you leap!Will be informing the local Landrover garage tomorrow,how did they not see this baffles me to be honest.

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May be time to find another garage ?

Maybe they did see but wanted some more of your cash.