As some of you know, I've had this van since January.
No MIL / CEL when test driven and driven home.
Within a few days I think the CEL came on.
It's been on ever since.

Is it possible that heavier corrosion on battery terminals can cause a CEL??
I had never heard of a thing like that, but started seeing that it can be a cause on Acuras for example.

When bought the posts were clean. Several months later the corrosion green build up is out of control. I am not really sure why this happens either.

It's in a warm(er) climate, driven low miles since owned, and sometimes it sits for 3-5 weeks at a time. I drive it daily when back in the area.

The battery was fully drained while sitting at some point at seller's. I did a 2A charge for about 6 hours and the battery has run strong ever since. Easy starts every time, even after sitting for 3-5 weeks.

Thoughts?

(and like my footer below this is a Ford factory build dedicated CNG version. It does not have any evaporative system installed, and some differences from gasoline versions).

 

A bad ground can cause problems , so it's possible

 

What are the trouble code(s)?
Knowing what the error codes are trying to tell you eliminates the guesswork.
I have found one of the best and cheapest ways to scan for trouble codes is with a Bluetooth OBD2 adapter and Torque app for Android. Also TorqueScan plug-in that requires the paid version of Torque.

 

Thanks, Very interesting product. Didn't know they were out there.
Do you have a recommended one that works well for you?

 

Usually corrosion on the terminals won't cause a light. If it's bad enough to keep the vehicle from starting then it's possible to trigger a low voltage code. The corrosion is caused by dissimilar metals on the battery terminal. Check the pinch bolt on the terminal and see if it looks like the original one that came with it or if someone changed it to a standard steel bolt. You can also buy a spray on battery terminal sealer at any automotive store. I use the stuff religiously and it works very well for corrosion issues caused by dissimilar metals.

 

I agree but nothing is usual on this van.....
I always start with the easy/obvious issues first

 

I have one exactly like this that has worked on every vehicle I have tried it on.
http://www.ebay.com/itm/251274981056?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AITThere are some higher priced ones that are "officially verified" to work, and there are some that are shorter so that they don't get in the way while driving. Or there are right angle adapter cables so you can "remote mount" the Bluetooth adapter away from the pedal area.

There is a free "trial" version of Torque (Lite) that will read and clear codes and offer some other useful info. The Torque Pro app is $4.95, TorqueScan plug-in is free but requires the paid version of Torque.
https://play.google.com/store/search?q=torque%20pro

So, in the neighborhood of $20 you can get real time OBD2 data if you already have an Android device. You can set dials to monitor GPS speed, speed the PCM thinks you are going, RPM, coolant temperature, and various other very useful info. If you don't already have an Android device you could pick up a cheap phone off Craigslist or even a good phone with a bad IMEI if you don't want to put it in service. Pretty much any Android device made within the last 5 years will work with Torque, it works on Android version 2 and up.

 

Since 1996 Car Handheld Car Diagnostic Scanner Tool Code Reader OBD2 OBDII | eBay
I have one of these which are now 20 bucks. I got mine for less but they didn't have the bluetooth ones yet.

You can get bluetooth ones for under 4 bucks on ebay but I prefer handheld.

 

Baking soda mixed with hot water and an old tooth brush will get rid of the battery corrosion; rinse with water and dry. Install an oiled felt pad (Auto Zone) under the cable clamp.