I'm digging in to an intermittent issue where I get code P0089-64 (2C), and sometimes P008A-07 (AC). Most of the research I've done indicates that I'm about to drop the tank and replace the low pressure fuel pump. However, I can't see spending the weekend on that if there are other issues making that problem occur.

I've plugged in my IIDTool and can see the battery voltage on the dash. I've seen it hit 12.0 while driving, so I wanted to try and log values to see what is causing what. I can see the voltage in the iPhone app as well. However, when I try to see the live values for the battery, it just reports N/A. Other values are present like engine speed and fuel pressure values. I'm wondering if the low voltage may be causing the fuel pressures to get low. I ended up doing a screen record of the home page of the app to see when it happens. It reliably gets to 12.0 as I am slowing down and subsequently backing in to my driveway. I also noted it one time while I was driving home cruising at about 45-50ish and 1800 rpm.

Has anyone had any issues getting the battery voltage in live values?

 

Firstly, when the engine is running, you are not reading battery voltage, you are reading charging voltage.
Secondly, charging at 12.0 v is significantly low.
A battery at rest and not being charged for a sufficient resting period (typically 6 hours) should read 12.6 v.

And yes, insufficient power can lead to all kinds of issues. Thats why the first pinpoint tests are always confirm proper battery health, before moving onto the next test.

Cheers

 

Exactly! so that’s why I’m trying to get some data about the battery. However, nothing regarding the battery is available. My live values screen should have “Batman” at the bottom because it just shows a bunch of NAs for the values, lol. Alternator current, battery voltage, % charge, etc are all NA engine running or not. It’s like something is not communicating but I don’t have any errors other than a TPMS initiator shorted to ground.

 

Apologies @mshale , you never really know the technical level of people.
Start with the obvious?? Cable? connection? Software update on device? Device paired with another VIN?

 

All good! No offense taken or meant, and I appreciate the help!
This LR4 came with a tool that’s paired with this VIN, it’s not under my account yet due to the weekend, and I have another one that’s paired with a RRFS I no longer own.
both are the Bluetooth versions and I did update the firmware on them yesterday.
I can now get the voltage, but it’s in the top corner of the app. I can also see it under the BCM called analog 11 or something like that. I’m guessing that’s just raw voltage on the bus, not something the battery management system is reporting.

Anyhoo, it’s weird that the charge voltage would just drop like a rock from 14 to 12 while driving.

I may have to reach out to GAP for the battery thing to see if they have seen that before.

 

Depending on the year of your vehicle, it may or may not have a BMS. If it does have a BMS, the generator is managed to the charging characteristics of an AGM battery.
And further managed based on load. I wonder if it dropped as the battery was at 100% or so??

 

Forget the gap go old school to start
Open the hood check both batteries they should be 12.4 volts or better, Ideally do this about an hour after shutdown and leave the hood up then you should get 12.6ish
Check the the voltage with a multimeter at start up it it should be 14+ volts at the main battery positive to negative
Then test positive to a engine compartment ground point this should all be 14+ volts ideally
Finally positive to engine block this should all be 14+ volts ideally

If any these are less than 14 in the first 15 minutes of runtime you have a problem

 

it looks like your supposition was correct. I ended up finding out after doing the old school battery and charging tests that I probably don’t have a bad battery. I had it tested at the autozone and tested it with my load tester at work. I also found that LR moved the battery voltage from the BCM to the Gateway Module. I am now able to log battery and alternator functions. When the voltage drops to 12.4, the target is also 12.3, so it is being told to do that.

Thank you for this suggestion. I was able to confirm that everything looks ok. I am curious if the little Aux battery can be removed without any issue. It tested well also and was a higher voltage than the main battery.