Cos215

I keep getting a malfunction with arrow on the display. I’ve replaced the front right airmatic, compressor , fuses and relays all without a scan tool.
just when I thought it was fixed I got another malfunction code after driving it 2 months with no issues.

Can anybody suggest a scan tool that will read the malfunction code and at least pinpoint the problem? The ones I’ve read reviews don’t seem to read suspension codes? And I had to return a cheap one I bought at Harbor Freight that didn’t read the malfunction for suspension and had to return it with a fee. I would like to spend under $200 dollars if possible. If anyone can suggest one before I just give up and trade this damn car in lol jk

2010 E550 Base Sedan W212