Well with the changing seasons, the random headlight issue and excessive parasitic current draw has come back. There was some hope that an unrelated update for the BCM would take care of the issue. That, pretty much as expected was found to be untrue
Luckily during the summer, I included two ways to charge my starting battery, a shore power charger
and solar charger option.
So at least I can keep the battery from being destroyed. (Wrong)
So back to the hunt. I pretty much realized that taking this back to Ford to track down would be fruitless, so I decided to dig in. In a previous life I worked on some complex issues, and the first rule of debug was to try and make the problem repeatable. Luckily for me with return of wet colder weather that has pretty much turned to every night.
One thing I looked at was the fact that rain returned. I know most people think it rains all the time here in Oregon. If you spent any time on the Transit Forum you heard of the water in the air filter issues. So, I did spend some time looking into this, mainly because the return of cold hit before the rain. I didn’t relay see the issue until I had both. That issue was I believed fixed in 2019, but it does get wet inside the engine compartment. I did clean out the weep hole and added additional hole for the windshield cowl draining system. I added a cover for a suspected connector, to keep it from getting wet. That appeared to be a red herring, as the problem was still prevalent.
I also completely disconnected the power steps, as they must sniff the CANBUS to determine if the door is open or closed. The power steps were added after first seeing this issue, so I was confident they had no issue with the problem. If I do have to back to Ford, I want to rule out any 2nd party culprits and keep the focus on the real problem. So, this may give you some insight to as where I am going the CANBUS. Unfortunately, or fortunately modern vehicles are dependent on CANBUS communication.
As you can see, there are five major Buses in this vehicle, a couple of high-speed busses and other medium speed buses. This doesn’t even include some of the private busses between modules. The gateway module is where all these buses come together, as it can also transfer information from one bus to the other. The gateway also has the DLC connection (OBDII) port connection.
The bus that I focused my concern at was HS1 CAN. It has the modules that are most likely involved in this issue, mainly the BCM, but it would be possible for an issue to transfer from one bus to the other. My first thought was to put a can bus sniffer on, to see if I could find out who was sending the BCM a bad message to turn the light on. That would be prudent, but you would have to catch the failure and have the documentation to understand the messages being passed. While I have a basic understanding of the protocol, it is not easy to get the information needed from Ford. Reverse engineering could take a sometime.
I was also using the data I had from capturing current data last year. That data led me to believe the problem was a possible bus problem as it would happen when there was known bus activity or at least I perceived there was activity based on the time cycle seen. The fact that temperature & humidity had a large effect on the issue. I spent many years running equipment in temperature chambers, so no convincing needed. My next thought was through a scope on the bus to see if anything looked out of the ordinary. Unfortunately, I don’t own a scope, and while I’m always looking for a reason to get one, I’m not sure this rises to threshold to purchase one. At least not yet.
I still have a few things I can do with a basic DVM, one would be to measure the voltages of the HS1 CAN +, and HS1 CAN – lines, that would be relatively easy, but determining that data depends a lot on the knowledge what is going on bus. So that leaves us with basic measurement on the termination of the bus.
CAN stands for Controller Area Network and it runs on a 2-wire high speed bus. To prevent reflections on the bus, it needs to be terminated on each end of the bus. Going back to one the previous diagrams you can see where the termination for the HS1 Can bus reside, the PCM module and the Gateway module.
When you go to measure these, you are going to need “needle probes” to easily get to these connectors, these will allow you to back probe the connectors. I couldn’t find my older needle probes, so I had to order some. While I was waiting, I took the Communication module off, and measured all the bus connection to verify that they have a 120-ohm resistance between the HS1CAN - and HS1CAN +, I check all the can busses going to the module.
I got my needle probes and was able to measure the connector going to the Gateway Communication module. The bus that I am looking at are pin 19 & 20, when I measured this, I got 60-ohm.
This was surprising in that I was expecting 120-ohm. 60-ohm would be what it should measure if the Gateway module was connected. Two 120-ohm resisters in parallel would equal 60-ohms, this leads one to believe there is an extra termination on the bus. Of course, to be sure, I connect the gateway module and measure between high & low and get 42-ohms.
I must say that I was kinds of surprised, as it seemed to simple. When checking the bus, you are really looking for something between 55 & 65 ohms. 42-ohm seems pretty far out, and for the most part this major bus has not shown any errors.
From the diagram above you can see that this bus goes all over the van. It seems like a simple divide and conquer attempt should be the best way to move forward. Seeing that the PCM is supposed to have the other bus termination I decide to go to a connector that I already know is easy to access C139. This is the same connector I thought might have moisture issues
Now when I remove this, I am really expecting to see 60-ohms on the bus, thinking that issue is on the other side of the connector. Instead, the issue travelled with the PCM side. I then moved to remove the AWD Module, no change in issue. So that kind of leaves me with the PCM. I made another appointment with Ford (different dealer) to again look at the issue, also pointing out the issue the termination of HS1-CAN.
My appointment didn’t go well, it was pretty much a replay of the first time I took it in. Yes, we believe there is a larger parasitic draw. You have stuff hooked up to it (Chargers). One out of your dual batteries is bad. The BCM might turn the lights on if the battery is low. I never received an answer about the Can-Bus termination. They recommended another dealer in the area that works mostly on Trucks and Campers.
A couple of weeks go by, the failure was replicated again in 36 hours, I again had to disconnect the batteries to keep this from happening. On a good note, I can attach get to the ground lead, from the driver side door, with the seat tilted. This is with some of the cover things removed.
The van is back from Northside Ford (NE Portland), after a couple of days the problem has not shown up. They did not address the HS1-Can termination value, but they did replace the body control module. The service manager did say they assumed because the bad module was on the bus, it was probably causing it. I did verify that the termination value is still wrong.
But changing the BCM appears to have fixed the issue, which completely makes sense, it is the module that turns on the lights. It also looks like my path down HS1-CAN termination not being the issue. Leave it to an engineer to dream up a more complex failure mode than just a bad module. In my defense this was aided by the lack of two technicians not finding a bad module.
In some ways I might have got lucky, I dropped the van off on a Friday morning at 9:00. The service manager informed me that I shouldn’t have used the online appointment form, as it was primarily for routine service. This would mean that my van wouldn’t get, looked at until the following week. Other than working on the interior, I have no big plans for the van. I am a little concerned about leaving it do to location, but their hours and fencing lead me to do so.
On Saturday I receive a message on my FordPass™Connect App that the vehicle has entered deep sleep mode to conserve battery energy. This is only 28 hours from dropping off with two new AGM fully charged batteries. I had the battery disconnected while waiting for the appointment. A sure sign that the lights have come on and are draining the battery. I don’t receive any information from Northside all week and call them on Friday, a week after dropping off. The message I receive is that they have started to look at it but no information, should be more information next week.
Monday afternoon, I get a call, that the BCM Body Control Module is bad, they are replacing so I need to bring in the secondary Keys for programing. I drop the keys off on Tuesday morning and I am informed by Wednesday it ready for pick up. Now it is Saturday morning, and I haven’t had the lights come on. Looks like they have fixed the issue.
From technician’s report:
Vehicle battery found to be discharged and will not jump start. Removed driver seat to access batteries. Found vehicle equipped with dual AGM replacement batteries. Removed batteries and tested with Midtronics Rotunda Battery Tester. Both batteries failed with DTC codes 304QF1940Q0C and 304QBLD46S0C. Replaced Batteries. Ran Oasis and found Batteries and Concern have been ongoing issue that two other dealers attempted to repair. Verified Headlights Randomly came on with keys out when running OASIS report. KOEO Self-Test Found multiple DTC’s. Due to batteries being drained performed battery draw test. Draw found to fluctuate between 1.011 amps and 0.064 amps randomly. When headlights come on draw exceeds 10 amps. Wiring Schematics show headlights controlled by BCM. Draw found to drop to .017 when C2280A is wiggled. Disconnected C2280A and inspected for corrosion or moisture, none present. Performed Pin Drag test, no fitment problems found. Fully seated connector and performed draw test again. Concern still present. Recommend replacing the BCM then testing for proper operation. Removed and replaced BCM using PMI procedure through FDRS. Programmed Keys and TPMS Sensors. Performed draw test. Draw found to be 0.006 Amps at rest, well within specifications. Wiggled C2280A and Verified Draw does not change. Headlight no longer randomly coming on. Installed seat and cleared DTC’s. Customer’s concern caused by faulty Body Control Module.
A couple of things to note, I was somewhat lucky that they waited a few days, and the van failed and drained the batteries. Obviously, the fact that the batteries were less than a month old probably helped. I was also considerably luck for the failure to occur at the shop. The fact that he saw the lights come on with the new batteries, while he was checking OASIS report, pretty much eliminated the train of thought from the last two dealers. The lights were not coming on because the voltage of the BCM was too low, instead it was now obvious that the lights coming on were drawing down the voltage.
Obviously, this tech was more persistent, and didn’t throw up his hands claiming it was a problem coming from the back of the van. No aftermarket things were connected to the Ford product. I will still need to go down the path of getting the HS1-CAN termination corrected. I assume this will be hard because I won’t have a failure to connect it to. You can’t start down the diagnostic flow chart if you don’t have a failure. And some crazy old customer saying so doesn’t count, at least not for warranty work.
So for the few people that have reported this issue, the headlights is the most visual problem, I have seen excessive draw even with out the lights coming on. My failure was a bad Body Control Module
-greg