Fuel Pump Draining Battery - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

TesTro · 09-28-2023, 01:37 PM

Hi all.

I have a 2012 SS 6.2L ~50K miles, and I have been struggling with a parasitic drain on my battery that causes it to die after about a day or so of turning the car off. I've mostly isolated the culprit as the fuel pump system, but want to take all steps to properly diagnose before pulling the pump out.

To start, I did a voltage drop test and found that the 20A fuse for the FSCM in the trunk was pulling around 4.0 with the car off. There are no other drains present in the system when I pull the fuse, and the car can happily sit for days with no issues.

I pulled the backseat out to get to the Fuel Pump Control Module, and I can hear the pump still running slightly even though the car had been off for a couple hours. Pulling the plug from the module similarly stops the drain on the system. I've also noticed that when I run the car and then turn it off, I can hear the pump try to power down after a few seconds, but it doesn't quite completely power off.

I picked up a OBD-II scanner, plugged the pump back in, cleared the codes, turned the car on, and it is showing P069E, P025A, U0109 after a couple of minutes.

I found a used Fuel Pump Control Module on eBay that was from an identical vehicle (with free returns :-) and plugged it in and the car started but I experience the same issues.

Car runs fine otherwise. I've never had any stalling out issues or issues starting the car. I should also mention that the guy I bought the car from in 2015 said the car had been tuned. I have no additional details and can't say that I know a lot about these sort of things.

Would really appreciate some advice on what I can do next. Thanks!

TesTro · 10-04-2023, 02:59 PM

Update:

I replaced the fuel pump using the trap door approach. Car runs fine, but the fuel pump is still not shutting off when I turn the car off.

Generally, it sounds like it is slowly turning off after about 10-15 seconds of shutting the car off, but it doesn't completely turn off. I tested this a bunch of times and there was actually one time the pump completely turned off, but it came back on about 10 seconds later without me doing anything.

The U0109 code I was getting was an archived code from disconnecting the module. P069E, P025A are the codes that keep coming back after I clear them. The module from eBay works exactly the same as the other and throws the same 2 codes.

Haven't done thorough testing of the wiring and I'm not really familiar with the process. I will continue doing some research. Would appreciate any guidance.

FasNuf · 10-04-2023, 05:59 PM

Is the fuel pump OEM with OE connections or aftermarket thats been spiced in?

TesTro · 10-04-2023, 10:39 PM

The pump is "A-Premium" brand off Amazon:

https://www.amazon.com/dp/B08BCQVNTY

I just pulled the old pump and dropped this one in with all the same connections.

FasNuf · 10-05-2023, 07:37 AM

Get the fuel pump relay tested. Not sure if this would even create your issue without seeing a schematic, but on some cars this would make a fuel pump stay on. Our pumps are pulse width modulated so I doubt it's the relay, but it's one less thing to figure out.

TesTro · 10-05-2023, 01:40 PM

By relay, do you mean the fuel pump control module (behind the passenger quarter), or is there a relay somewhere else I should be testing? I tried a completely different module (used) from an identical vehicle and have the same results. The listing claimed the module was tested and working.

FasNuf · 10-05-2023, 02:33 PM

Sorry, Not sure why I thought there was a relay in addition to the FPCM under the hood.

FasNuf · 10-05-2023, 02:41 PM

I'll pull the schmatic tonite and see how the FPCM is wired. I do know the fuel pump has a priming timer run through the ECM, but I'd hate to tell you to replace the ECM and not have it be the issue.

TesTro · 10-05-2023, 05:07 PM

Thanks! That will be really useful since I haven't been able to find any info on this.

More updates:

New pump and module have no problems with highway driving. Codes don't show until I shut the engine off.

FasNuf · 10-05-2023, 06:19 PM

Check the wiring to the FPCM. Make sure its not grounding somewhere. The Grn/wht wire is the trigger for the pump.

FasNuf · 10-05-2023, 06:31 PM

These are 2013 schematic which are closer to your year than my manual. The top schmatic looks right.
Notice the Grn/Wht wire from the ECM to the FPCM. I'd start looking and following the harness back to the ECM to make sure its good.

https://ls1tech.com/forums/conversio...cm-wiring.html
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acutron42 · 10-06-2023, 06:29 AM

Here are a few pics. Let me know if you would like to see anything else.

TesTro · 10-06-2023, 09:56 PM

Thanks guys! I have a weird update though:

Got in the car today and plugged the pump module in and it didn't automatically start making noise. The car started fine and then my ABS/brake and stabilitrak lights came on. Threw a code u0121 (Data bus, ABS module - no communication). Drove it like that for about 30 minutes, next time I got in the car the ABS & stabilitrak lights are gone, as well as the fuel pump issue. First time seeing this ABS stuff. The car has had the parasitic drain issue for months.

Will see what I can test over the weekend using the diagrams and check back in. Thanks again.

FasNuf · 10-06-2023, 10:33 PM

Anytime you disconnect a module like the FPCM with the battery connected, it will give the lost communication code. The FPCM is always on. If you want to avoid the code, disconnect the battery and let sit for a few minutes before disconnecting anything. Reconnect everything before connecting the battery last.

Pulling thre fuse for the FPCM will do the same thing but is a little harder to get to.

09-28-2023, 01:37 PM	#1
TesTro Drives: 2012 Camaro SS Join Date: Sep 2023 Location: NY Posts: 11	Fuel Pump Draining Battery Hi all. I have a 2012 SS 6.2L ~50K miles, and I have been struggling with a parasitic drain on my battery that causes it to die after about a day or so of turning the car off. I've mostly isolated the culprit as the fuel pump system, but want to take all steps to properly diagnose before pulling the pump out. To start, I did a voltage drop test and found that the 20A fuse for the FSCM in the trunk was pulling around 4.0 with the car off. There are no other drains present in the system when I pull the fuse, and the car can happily sit for days with no issues. I pulled the backseat out to get to the Fuel Pump Control Module, and I can hear the pump still running slightly even though the car had been off for a couple hours. Pulling the plug from the module similarly stops the drain on the system. I've also noticed that when I run the car and then turn it off, I can hear the pump try to power down after a few seconds, but it doesn't quite completely power off. I picked up a OBD-II scanner, plugged the pump back in, cleared the codes, turned the car on, and it is showing P069E, P025A, U0109 after a couple of minutes. I found a used Fuel Pump Control Module on eBay that was from an identical vehicle (with free returns :-) and plugged it in and the car started but I experience the same issues. Car runs fine otherwise. I've never had any stalling out issues or issues starting the car. I should also mention that the guy I bought the car from in 2015 said the car had been tuned. I have no additional details and can't say that I know a lot about these sort of things. Would really appreciate some advice on what I can do next. Thanks!

10-05-2023, 06:19 PM	#10
FasNuf Drives: 2014 Camaro ZL1 Join Date: Jul 2019 Location: Oregon Posts: 1,702 View My Garage	Check the wiring to the FPCM. Make sure its not grounding somewhere. The Grn/wht wire is the trigger for the pump. __________________ . . . . https://www.youtube.com/channel/UCgN...etl17hA/videos

10-05-2023, 06:31 PM	#11
FasNuf Drives: 2014 Camaro ZL1 Join Date: Jul 2019 Location: Oregon Posts: 1,702 View My Garage	These are 2013 schematic which are closer to your year than my manual. The top schmatic looks right. Notice the Grn/Wht wire from the ECM to the FPCM. I'd start looking and following the harness back to the ECM to make sure its good. https://ls1tech.com/forums/conversio...cm-wiring.html . . . . . . . . . . . . . __________________ . . . . https://www.youtube.com/channel/UCgN...etl17hA/videos

10-06-2023, 06:29 AM	#12
acutron42 Drives: 2013 Camaro 2SS AGM Join Date: Apr 2020 Location: WNY Posts: 922	Here are a few pics. Let me know if you would like to see anything else. Attached Images __________________ 2013 2SS GPI built & tuned 415, spec'd by Andrew Cammer. GPI ported intake/tb/heads, Tooley springs, CHE trunnions, Callies rotating assembly, Diamond pistons, GPI SS3 VVT, ATI 10% ud damper, Circle D 3800, Kooks ceramic coated lt's with green cats, Mishimoto rad & oil cooler, Derale trans cooler, Holley efi rails. DSS driveshaft, trutrac with 3.91's, G-Force renegades, Hendrix solid cradle bushings Bmr: poly diff bushings, Strange adjustable coilovers, sub frame connectors, ZL1 npps, controlled with a vac pump & mac boost control solenoid.

10-04-2023, 02:59 PM	#2
TesTro Drives: 2012 Camaro SS Join Date: Sep 2023 Location: NY Posts: 11	Update: I replaced the fuel pump using the trap door approach. Car runs fine, but the fuel pump is still not shutting off when I turn the car off. Generally, it sounds like it is slowly turning off after about 10-15 seconds of shutting the car off, but it doesn't completely turn off. I tested this a bunch of times and there was actually one time the pump completely turned off, but it came back on about 10 seconds later without me doing anything. The U0109 code I was getting was an archived code from disconnecting the module. P069E, P025A are the codes that keep coming back after I clear them. The module from eBay works exactly the same as the other and throws the same 2 codes. Haven't done thorough testing of the wiring and I'm not really familiar with the process. I will continue doing some research. Would appreciate any guidance.

10-04-2023, 05:59 PM	#3
FasNuf Drives: 2014 Camaro ZL1 Join Date: Jul 2019 Location: Oregon Posts: 1,702 View My Garage	Is the fuel pump OEM with OE connections or aftermarket thats been spiced in?

10-04-2023, 10:39 PM	#4
TesTro Drives: 2012 Camaro SS Join Date: Sep 2023 Location: NY Posts: 11	The pump is "A-Premium" brand off Amazon: https://www.amazon.com/dp/B08BCQVNTY I just pulled the old pump and dropped this one in with all the same connections.

10-05-2023, 07:37 AM	#5
FasNuf Drives: 2014 Camaro ZL1 Join Date: Jul 2019 Location: Oregon Posts: 1,702 View My Garage	Get the fuel pump relay tested. Not sure if this would even create your issue without seeing a schematic, but on some cars this would make a fuel pump stay on. Our pumps are pulse width modulated so I doubt it's the relay, but it's one less thing to figure out.

10-05-2023, 01:40 PM	#6
TesTro Drives: 2012 Camaro SS Join Date: Sep 2023 Location: NY Posts: 11	By relay, do you mean the fuel pump control module (behind the passenger quarter), or is there a relay somewhere else I should be testing? I tried a completely different module (used) from an identical vehicle and have the same results. The listing claimed the module was tested and working.

10-05-2023, 02:33 PM	#7
FasNuf Drives: 2014 Camaro ZL1 Join Date: Jul 2019 Location: Oregon Posts: 1,702 View My Garage	Sorry, Not sure why I thought there was a relay in addition to the FPCM under the hood.

10-05-2023, 02:41 PM	#8
FasNuf Drives: 2014 Camaro ZL1 Join Date: Jul 2019 Location: Oregon Posts: 1,702 View My Garage	I'll pull the schmatic tonite and see how the FPCM is wired. I do know the fuel pump has a priming timer run through the ECM, but I'd hate to tell you to replace the ECM and not have it be the issue.

10-05-2023, 05:07 PM	#9
TesTro Drives: 2012 Camaro SS Join Date: Sep 2023 Location: NY Posts: 11	Thanks! That will be really useful since I haven't been able to find any info on this. More updates: New pump and module have no problems with highway driving. Codes don't show until I shut the engine off.

10-06-2023, 09:56 PM	#13
TesTro Drives: 2012 Camaro SS Join Date: Sep 2023 Location: NY Posts: 11	Thanks guys! I have a weird update though: Got in the car today and plugged the pump module in and it didn't automatically start making noise. The car started fine and then my ABS/brake and stabilitrak lights came on. Threw a code u0121 (Data bus, ABS module - no communication). Drove it like that for about 30 minutes, next time I got in the car the ABS & stabilitrak lights are gone, as well as the fuel pump issue. First time seeing this ABS stuff. The car has had the parasitic drain issue for months. Will see what I can test over the weekend using the diagrams and check back in. Thanks again.

10-06-2023, 10:33 PM	#14
FasNuf Drives: 2014 Camaro ZL1 Join Date: Jul 2019 Location: Oregon Posts: 1,702 View My Garage	Anytime you disconnect a module like the FPCM with the battery connected, it will give the lost communication code. The FPCM is always on. If you want to avoid the code, disconnect the battery and let sit for a few minutes before disconnecting anything. Reconnect everything before connecting the battery last. Pulling thre fuse for the FPCM will do the same thing but is a little harder to get to.