[Ajax]

Hi
I'm fairly new to Range Rovers - bought my first two months ago: 1997 P38 DSE auto, 154k miles. Recently it went into but wouldn't come out of Low Range (showing the select neutral warning message).

The transfer motor works when powered directly (a PP3 battery on the connector terminals), the transfer motor position switches appear to function normally, but the transfer motor ECU (AMR6353) has a visibly burned out power transistor.

I've moved the motor socket to high and have refitted it, so I'm back in High range again and everything appears fine. The main agent tells me AMR6353 has been superceded by AMR6459 and that hasn't itself been superceded. I've ordered a second hand replacement ECU.

As I understand it, the transfer ECU usually fails because the transfer motor fails, usually with a short. The transfer motor seems fine, but I don't fancy frying my next ECU if it's not, or unnecessarily replacing the transfer motor if it is fine: Does anyone know what the normal resistance for a transfer motor is?...
Ajax

 

[Ajax]

Re: Transfer motor resistance

To add:
I had measured the motor resistance when I had it on the kitchen table & it seemed low, but of course, I couldn't remember what it was. I've measured it again & it's 0.3 ohms, which seems rather low to me, equating to a 40A draw. Is this normal or not, or am I missing something else?

 

[munichp38a]

Hi and welcome!

The transfer case ECU has been updated, earlier versions had insufficient cooling and can burn out in the way you describe, so you should get the updated version.

And the motor draws quite a lot of power, yes.

Sigi

 

[Ajax]

Thanks Sigi. With a replacement transfer motor ECU (AMR6459, which has a huge heatsink) it all works fine, so it looks like 0.3 ohms for the motor is within serviceable limits.
Ajax