960 Limp Mode

[DWeed144]

Hi all,
So i have been enjoying my auto 960 for a few months but I am not having a little trouble.
When I bought it, it went into limp mode almost immediately, but my doing the gear shifter trick (of running it from P to L a few times), I was able to get it back to normal. However it then started happening more regularly, and is now stuck permanently with the limp mode light on and terrible shifting.

What should I do? I could remove the switch but am I right in thinking it isn't easilly repairable?
And if I buy a replacement do I just get one of the ones on ebay or is there a better source?

What have others done in this situation?

[Laird Scooby]

An ATF change would probably be a good place to start but also you need to hook it up to some sort of diagnostic tool to read the codes from the auto box ECU and find out why it's going into limp mode.

I'm not familiar with the 960 but do you know which box it has in it? I may know a bit more about it if i knew which box it has.

Also it might help others if there happens to be a possibility of more than one type of box being fitted.

Have you checked the fluid level at all?

Is the engine getting up to temperature properly? Some autos i've come across use the EFi coolant temperature sensor to determine if the engine is hot or cold and if it's not hot will go into limp mode - that's why i run hotter than standard 'stats in my cars, one of the reasons anyway.

Are there any other symptoms? Even if seemingly unrelated things like perhaps the engine MIL lamp coming on/staying on or an ABS light or anything?

[DWeed144]

It is the Aisin AW30-40 I think.

The fluid level is spot on and looks to be a very healthy colour.

I have got the fluid for a change but was going to do this when I had solved the limp mode.

The temperature is fine. The only other fault is the Lamda sensor light is on.

I guess I should be getting an OBDII reader should I?

The only reason I was fixed on the PNP switch is that by pushing the shifter from P to L 10 to 15 times has fixed it on the last few occasions. Which would suggest that unless something new has occurred, the PNP switch has just failed more permanently than before.

[TopSkateDog]

I used a generic OBDII reader for my 96 960, code was the PNP switch.

After resetting the code, and doing the shifter sweep thing, I've not had any reoccurrence. Transmission behaves perfectly in all other respects.

[Laird Scooby]

I'm not familiar with the AW30-40 although i believe it's similar to the AW71 in my 760 but with more sophisticated control.

It could well be the neutral switch/PNP switch/neutral safety switch/inhibitor switch or whatever this one happens to be called, i've had similar problems on my Rovers with that in the past but some contact cleaner solved it. However that's quite an open switch so was susceptible to dust, dirt etc.

First port of call has to be a diagnostic test to actually find the problem. ;) :D

[DWeed144]

So I just discovered the ODB-I fault code reader thing, I can't believe how good it is!

So I got a few fault codes.

The ones that seem to be the most cause for concern are below

1-1-4 Program selector open-circuit or short-circuit to ground

1-2-2 Solenoid S1 open-circuit

1-4-3 Oil temperature sensor circuit, open circuit

3-1-3 FAulty signal from gear position sensor

I've reset it all and the car is working happily again now, but for how long? I assume these problems haven't fixed themselves...

Thanks for the tips on the diagnostics though!

[Laird Scooby]

Almost as if a multiplug hasn't been refitted somewhere.