Santa brought me an OBDII code reader this year. I hooked it up to the car, ran some of the features, and I like it. One of the features is a Diagnostic Monitor Test. I ran that and saw that all the Diagnostic Monitors tested well except for $19 and $39 which showed "low" and gave some numerical values and what the acceptable limits are for that monitor. So, what are $19 and $39? Is there a list of the Diagnostic Monitors anywhere? There are lists of the OBDII codes all over the place, but I haven't found out which monitors go with which numbers. Any ideas?

The reader should have a manual to let you know. My reader made by Actron, shows an initials such as RPM or LTF (long term fuel calculation). If not, contact the ODB tool manufacturer or visit their web site.

Hi Kurts2. Thanks for the reply. I have the Actron CP9180 reader. After running the Diagnostic Monitor Test and viewing the results, most of the monitors registered OK. $19 and $39 showed "low" in the results. The manual (page 4-25 for my reader) says, "Vehicle manufacturer is responsible for assigning test and component IDs." Now I need to find out what those components monitor. I'd really like to have a list of ALL the IDs and what they monitor, but I haven't found one online. I also have a Haynes manual for the car which shows all the OBDII codes, but I haven't found the monitor codes.

For example, Test $39 says:

ID: 00
MAX: ------
MEAS: 4
MIN: 6
STS: LOW
MOD: $10


Test $1a

ID: 00
MAX: ----
MEAS: ff
MIN: 6
STS: OK
MOD: $10

Perhaps I didn't set up the tool correctly and that's why the IDs are all 00? Or is there a list of the Test IDs somewhere?

I have the Actron 9145 (a bit older), and mine has never displayed as your is. It may be the way you set up the tool for the vechile. As for a list, I have never seen one before, but I have never looked because as I mentioned, I never saw what you are seeing. I'm sorry I couldn't be of any help. One last idea though, call Actron and ask them why you are getting code and not plain english. Good luck, let me know how it turns out.

Ok Kurts2, here's what I found out. I called Actron and asked them where to find these numbers. The guy said that those codes are specific to a particular manufacturer and sometimes to a particular model and year! So, you have to subscribe to a service like AllData.com and then you can look up those codes. There are other benefits, too, I guess. Anyway, the code reader gets you only so far, and then you still have to throw money at the problem!

But wait! It gets better! I called my local public library and they have a subscription to AllData and I can just use their account for free! Woo hoo! Unfortunately, that won't help me when I'm working on the car at 1:00 am.....