circuit short to ground

[Rustedpalm]

My 2018 XLT 3.5 v6. MIL is on. Codes are..

1. C1D00:11 Park brake apply switch (circuit short to ground)
2. B143B:11 Autolamp on input (circuit short to ground)
3. B143C:11 Autolamp off input (circuit short to ground)
4. P0430-EC Catalyst system efficiency below threshold (bank 2)

I also have TPMS codes but I know those sensors are not working because of low batteries.
When I first checked the codes the parking brake was applied and the autolamps were on and these codes showed up. I released the parking brake and that code went away. I then turned the headlights to off and the autolamp code went away. So my question is do I have a short to ground FAULT when I apply the parking brake and autolamps, or does the BCM want them to be in the off position when testing for codes. Which would indicate that those systems are operating normally?
A few days after these codes showed up the car battery completely died. Only showing 2v. I replaced the battery and did a parasitic draw test to see if that was the problem all along. It only had a draw of ~20 mA which I believe is in the normal range. It did cycle between ~4mA up to the ~20mA but again I think that is normal. /

Could there be a loose ground somewhere causing this issue? Could there be a short to ground that would cause these issues and the 0430 code?

 

[ProjectSHO89]

Your MIL is on because of the P0430 DTC, not the other stuff. The DTC P0430 is there because your catalytic converter on bank 2 is no longer working well enough to pass.

If you do not have any operational symptoms related to the parking brake indicator or the autolamp function, chalk those fault codes up to either testing procedure issues. Just reset them and look for future issues.

Sometimes, batteries just die for no apparent reasons.

 

[Rustedpalm]

Your MIL is on because of the P0430 DTC, not the other stuff. The DTC P0430 is there because your catalytic converter on bank 2 is no longer working well enough to pass.

If you do not have any operational symptoms related to the parking brake indicator or the autolamp function, chalk those fault codes up to either testing procedure issues. Just reset them and look for future issues.

Sometimes, batteries just die for no apparent reasons.

Oh ok, thanks ProjectSHO89. That is exactly what I was thinking. Especially after seeing yesterday that while testing with the hood up a code for it was also present. Also I believe the BCM fault is there because of the failed TPMS.
Now, on to the cat. Sort term trims are around ~ +2 at idle. Which all seems normal. I'll have another look at the O2 voltages today. I suppose at 182,000 miles a plugged cat is possible.

 

[Steve8316]

...do I have a short to ground FAULT when I apply the parking brake and autolamps, or does the BCM want them to be in the off position when testing for codes.

The procedure for reading codes does NOT begin with "plug in the code reader" - there are several steps before that, including ensuring that all the accessory systems' controls are in the correct positions (usually OFF). When you do the test wrong, you can get irrelevant codes.

...the car battery completely died. ... It only had a draw of ~20 mA which I believe is in the normal range.

Sounds coincidental; 20mA is well below the maximum.

Could there be a loose ground somewhere causing this issue? Could there be a short to ground that would cause these issues and the 0430 code?

No, a loose ground can't cause a short to ground; it would cause an open ground, or high voltage faults, or things not working.

 

[1sicbronconut]

Oh ok, thanks ProjectSHO89. That is exactly what I was thinking. Especially after seeing yesterday that while testing with the hood up a code for it was also present. Also I believe the BCM fault is there because of the failed TPMS.
Now, on to the cat. Sort term trims are around ~ +2 at idle. Which all seems normal. I'll have another look at the O2 voltages today. I suppose at 182,000 miles a plugged cat is possible.

The P0430 code is a "efficiency" code meaning that the bank #2 or front catalytic converter isn't doing it's job correctly ( not plugged) and 99.9% of the time leads to replacement. The short term fuel trims will look good since the fault is actually with the converter so the up-stream oxygen is doing it's job it's the down-stream sensor that shows the converter fault with the mileage on your explorer I'd plan on replacing both sensors along with the converter since you have it out and they might be a PITA to pull due to the mileage.

 

[Rustedpalm]

Thanks for sharing. I didn't realize I did the test wrong. MIL came on so I checked it. It just happened that the brake and auto lamps were on at the exact same time. Live and learn.

 

[Steve8316]

I didn't realize I did the test wrong. MIL came on so I checked it.

Remember that reading fault codes is NOT an owner-level task. If it were, it would be explained in the owner guide (which you should read). Anything not in there is technician level or higher, requiring specific training, tools, & equipment. Some (like oil changes & burned bulbs) require cheap tools & little training; some require expensive equipment & extensive training; and some are in-between. But for every task, there's a right way to do it, in addition to all the many wrong ways. So before diving in, do a lot of research & reading. YouTube is just a starting point - it's not comprehensive.

For example: before reading powertrain fault codes, the engine & transmission should be at operating temperature. But again - that's just 1 condition on a long list for that task.

 

[Rustedpalm]

Remember that reading fault codes is NOT an owner-level task. If it were, it would be explained in the owner guide (which you should read). Anything not in there is technician level or higher, requiring specific training, tools, & equipment. Some (like oil changes & burned bulbs) require cheap tools & little training; some require expensive equipment & extensive training; and some are in-between. But for every task, there's a right way to do it, in addition to all the many wrong ways. So before diving in, do a lot of research & reading. YouTube is just a starting point - it's not comprehensive.

For example: before reading powertrain fault codes, the engine & transmission should be at operating temperature. But again - that's just 1 condition on a long list for that task.

Cool. Sounds like your a professional tech. Thanks again for helping me out.

 

[javaleo]

Before you replace the CAT. Check the Bank 2 Sensor 2 O2 sensor. A "rodent" may have chewed on the wires. It did on mine.
It is the one right by the Oil Filter.

 

[Rustedpalm]

Before you replace the CAT. Check the Bank 2 Sensor 2 O2 sensor. A "rodent" may have chewed on the wires. It did on mine.
It is the one right by the Oil Filter.

Thanks, I’ll be sure to check it out first. I don’t want to just throw parts at the problem.

 

[ProjectSHO89]

Before you replace the CAT. Check the Bank 2 Sensor 2 O2 sensor. A "rodent" may have chewed on the wires. It did on mine.
It is the one right by the Oil Filter.

That would trigger its own fault code and the catalyst efficiency test would not have run.

 

[peterk9]

Thanks, I’ll be sure to check it out first. I don’t want to just throw parts at the problem.

Welcome to the Forum.

Peter