Tech Please Help. Engine system service required
 

Hi,

I have a 99 S80 T6 with a 140,000 miles. I've been receiving an engine system service required message on and off. It will eventually go off by itself. When it was on I took it to Autozone to have the codes read, but the reader said that no codes was present. I thought this was strange becase I know that the ABS module needs to be replaced. Now that the weather has cooled off I haven't seen the message come it. It seemed the message coming on was correlated with extreme temps. Above 100. Does anyone know what this might be?

RE: Tech Please Help. Engine system service required
 

Most gerenic scanners won't read the S80's all the time.
So there might really be codes in there but the scanner won't read them.