No Heat

[cjshaw14]

Had similar issue last year with no heat on 09 E70, replacing the valve did the trick, sorry that didn't work. But saw your ISTA comment with no comm to modules, ran in circles until I found what it was, be sure latency is set to 1. Open “Device Manager”, then USB Serial Port properties, go to “Port Settings” tab and click
“Advanced...”. Change latency timer to “1”

[LightlyToasted]

Originally Posted by cjshaw14

But saw your ISTA comment with no comm to modules, ran in circles until I found what it was, be sure latency is set to 1. Open “Device Manager”, then USB Serial Port properties, go to “Port Settings” tab and click
“Advanced...”. Change latency timer to “1”

Thanks - I'll check it out, but it's only some of the modules that ISTA cannot communicate with.


For my no heat problem, I'm beginning to suspect the auxiliary water pump. I'll get some heat after a 1/2 hour drive as if only a minor amount of coolant is making it to the heater core. Also, I cannot hear the pump when I activate heating in "rest mode". Before I dig through the wheel arch to get to it, does anyone know precisely when it's supposed to be on? I'm expecting +12V when calling for heat and in rest mode.

[LightlyToasted]

Originally Posted by cjshaw14

Had similar issue last year with no heat on 09 E70, replacing the valve did the trick, sorry that didn't work. But saw your ISTA comment with no comm to modules, ran in circles until I found what it was, be sure latency is set to 1. Open “Device Manager”, then USB Serial Port properties, go to “Port Settings” tab and click
“Advanced...”. Change latency timer to “1”

@cjshaw14 - thanks! This worked, and now ISTA can talk to all of the modules. The only code sticking around is E723 in IHKA - No message - condensator sensor. I don't think this is my problem.