Not Engaging 4wd

[push2pass]

Hi Gang

Looking for a bit of advice,

07 D40 RX manual and unable to select 4wd, still able to get into low range but not 4wd (all these years I've been wanting to select low range 2wd but not at the cost of losing 4wd)

The following fault codes are coming up

U1000 CAN COMM CIRUIT
P1814 4WD Detect SWITCH
P1818 SHFT ACT POSI SW
P1808 VHCL SPEED SEN-ABS
P1820 ENGINE SPEED SIG

At the time when these codes where read i had an ABS problem which has now been fixed so i think that should of removed at least one code?

Please help anyone

 

[nathand22]

After the ABS problem was fixed did you do a ECU reset?

 

[andrew0]

I'd like to know how to replicate this!

You shouldn't be able to do this so at my guess something has broken in your transfer case. Have you changed the oil in it?

 

[Old.Tony]

The ABS sensor fault will prevent you from entering 4WD and will also cause the speed signal issue because the D40s get the speed from the 4 ABS sensors and not the gearbox revolution sensor.

If you've fixed the ABS sensor, try resetting the ECU (switch engine off, disconnect vehicle battery, press foot brake, reconnect battery). If that doesn't work, the P1814 error might still be there, which is the sensor in the transfer case.

I don't think the cars can actually go into 2LOW. The mechanism that engages any of the transfer case functions is a single arm inside, which rotates 90 degrees to engage 4WD at a 1:1 ratio then a further 180 degrees to change into low range (2.625:1 ratio). The transfer case doesn't physically allow 2LO.

It'd be interesting if yours actually DOES - easiest way to tell is to try driving it, how fast can you get to in 2nd gear? If it (comfortably) only gets to about 20km/h, there may be something seriously wrong in the transfer case and it'll need a mechanic who knows 4WDs.

 

[push2pass]

Yes i reset the ECU by doing the following

Ign on
Pump gas 5 times
wait 7's
Hold gas 10s

Plus when i was working on the ABS i had the disconnected for a couple of days

As Tony has explained above I didn't think it was physically possible to select Low range without having 4wd, but I've definitely. I even did a little burnout on the grass to prove it to a mate.

The only thing I can think of is major damage in the transfer box or front diff but there was no warning signs from either.

Does anyone one have a chart of account for the fault codes?

Cheers

 

[Old.Tony]

1000 is more often because of dirty contacts somewhere in the wiring looms, more often than not the ECU ground in the D40.

1814 is the sensor in the TF case. It does seem to be a reasonably common fault. Replacement of the switch is the usual fix, I do not know if cleaning it will succeed.

1818 is also in the TF. I'd guess that if you truly have 2LO, the 4WD engagement pawl (it slides back to engage the chain connecting front and rear drive shafts) has demolished itself somehow, and the debris could be affecting this and the wait sensor.

The other two are related to the ABS. You will have to clear the codes from the ECU using a scan tool or an app like Android's Torque with a bluetooth OBD adapter. If they reappear, maybe your ABS is still seeing a problem - might be time to check the front wheel bearings (both sides). The speed system in the ECU takes the aggregate reading from the four ABS sensors, works out an average of the closest 3 and presents that as the vehicle speed. It's surprisingly accurate on standard tyres.

 

[push2pass]

So i've pulled the cover of the actuator box started up the car (it wouldn't work on just ign)
Then got someone else to flick the switch, while i watch. It did it's turn to engage 4wd then another to engage low.

So then I removed the actuator completely so i could get a screw driver in to turn the engagement shaft. It is only allowing me to do a 90 degree turn which i can hear something engaging & disengaging then i can get another 90 degree turn further that is spring loaded and flicks back once i take the pressure off.

In total only at 180 degree turn, unfortunately the more i investigate the more i think i could be up for a transfer box re build or maybe another 2nd hand transfer box

anyway neither sounds cheap & starting to get well out of my skill level

 

[Old.Tony]

Certainly sounds like something's not behaving itself. Do you have a mechanically-inclined friend? If you take to a shop and they find that there's a tooth broken in the reduction gear (say) they'll not want to put it back together without actually fixing it.

I'm thinking that it must be something in the reduction gear or the engagement pawl, because otherwise you'd experience trouble while driving. The front shaft does turn over while you drive, it's just disconnected from the rear shaft.

 

[push2pass]

First I fixed the ABS to get the transfer box actuator working

Then I cleaned & free up the actuator and got it work properly, still no 4wd!

jacked up the rear engaged 4wd and both drive shafts are spinning, so must be diff or axles (i'm guess diff) the weird thing is I've had diff go on me & usually there is warning signs, lot of noise when it happens & you can hear parts crunching if you continue to drive on it. This one is dead silent

 

[4 naving]

So the front shaft spins but not the wheels. That would certainly point to a front diff.
Maybe drop the oil and look for metal..
But yes you would think it would make some noise especially when you put drive through the transfer and move the wheels.

 

[nathand22]

both times i broke the diff on my D40 there was no noise AFTER it snapped, the first one snapped the pinion shaft and I drove it home no noise but i did wire up the tail shaft to stop it dropping onto the bashplate.
not sure exactly what went in the second one but it went crack, oil pissed out of it and that was that, drove it about 100km then a p plater missed a stop sign and wrote it off but until that point you wouldnt of known the diff was smashed to bits.

BUT in both cases i did definitely herd it go bang when they first snapped.