Digital fuel gauge at bottom of cluster does not match OBD fuel percentage

ormandj · 2024-11-03T01:18:05Z

I have a 2024 1500 AT4X 3.0 diesel I picked up last Friday. The last day, I've noticed my fuel gauge does not appear to be dropping on the digital display, though my miles remaining indicator does. If I use an OBDII scanner, I can see the PID associated with fuel percentage appears to be accurate. The gauge was stuck at around 95%, but it was reading 80%.

I filled up the tank, and the digital gauge updated to full, but even after driving 60 miles, it hasn't budged, though OBDII and miles remaining both show the fuel level has dropped, so I know the sensor in the tank must be working correctly. It seems like something is 'stuck' with the instrument cluster fuel gauge, or there's some weird behavior going on here that's unexpected. It is strange, though, that when I filled up (the gauge was stuck at around 90-90% if I were to eyeball it) - it went to full, so clearly it at least partially responds.

Full transparency, I had the serial data recall performed, and they did update the radio (this was when -4 was the latest) last Friday. That said, the gauge was working properly afterwards, or at least, was dropping as I burned diesel. The other notable thing that's occurred was I had the battery disconnected for an hour or so the other day while ensuring all the fuses/bolts/etc were tight and I had an emergency meeting come up (old habit from owning Jeeps which are notorious from coming from the factory with things not seated properly.)

The last thing I can think of that's different is my driveway is at a fairly steep angle, and last night I reversed in and parked (tank would be much higher than the engine and depending on sensor location, perhaps reads as lower fuel). I'm wondering if the gauge does some kind of weird compensation if it detects fuel level increasing significantly (when the car leveled out after I drove off) while the car is running? I normally park forward, which has the engine/front of the truck higher than the back/tank.

Has anybody else run into this or have any suggestions on what I might do? I did the hold down the 'hangup' button reset of the infotainment, but that doesn't seem to have changed a thing. It just seems really odd that filling up caused the gauge to go to full, but burning gas does not appear to make it drop, or at least it hasn't budged in the first 70 miles or so I've driven on this new tank of gas. Do I need to perform some kind of procedure to re-calibrate it after pulling a battery for a longer period of time? Or parking reversed up hills?

Edited yesterday at 01:18 AM by ormandj

ormandj · 2024-11-03T20:06:26Z

I’ve noticed after driving 70+ miles it has slightly moved downwards(perhaps a mm at most), so it definitely is moving, but there’s no way it’s even close to an accurate representation of remaining fuel. I’m showing 410 miles remaining, which started at 480, so the miles remaining appears to be working as expected.

redwngr · 2024-11-03T20:38:51Z

Congrats on the new truck!

I've never heard of the fuel gauge having that issue.

60 miles is only 10 % of a 600 mile tankful.

I'd wait for a couple of tankfulls to see if a pattern can be identified.

Miles remaining is based on 'recent' mpg -- some combo of instant, 25 mile, 50 mile, etc.

When current mpg changes significantly the 'estimated range' will change slowly to reflect this.

Computer can't possibly know how the truck is going to be driven for the rest of the tank....faster/slower/grades/wind/trailer etc etc.

I reset 'tripmeter 1' every time it gets filled (and record miles, trip mpg and fuel added so that 'had calculated can be compared with the DIC.

I sometimes check the tripmeter + range number -- so I evaluate this tankfulls 'estimated trip miles' to what it usually does with the way I usually drive.

This is a little less than 27,000 miles. Usually the truck is doing a little better than the DIC suggests.

Lifetime hand calc average is 29.2.

Clearly there is tank-to-tank variation depending on usage.

ormandj · 2024-11-03T21:37:30Z

I’ve been doing pump calculated mileage over the last 600 miles and average a little over 20mpg. Lots of around town driving. I’m just surprised the fuel % might be 80% via OBD2 but the fuel gauge itself will show nearly full. I’ll give it a few more tanks, it wasn’t like this before, that’s why I was confused.

At my current mpg I should get about 480 miles if I depleted the tank entirely, which I expect there is a reserve on. The estimated mileage is pretty close to what I’d expect.

Edited yesterday at 09:53 PM by ormandj

ormandj · 2024-11-03T22:48:23Z

Trip 1 is since I filled the tank.

Readout is from OBD2.

64BAwagon · 2024-11-03T23:49:15Z

The fuel level in gallons is on the OBD data because it shows up on my scangage. The gauge at the bottom of the dash is off like every other GM truck I have owned. It stays on full too long and drops like a stone when it gets below 3/4 until it gets to 1/4. The scangage is fairly accurate at reporting the gals left, I check it when I fill up.

I use my scangage mostly since the OEM gauges are so weak and lack any real numerical readings, just guesstimates typical of a minivan.

kickass audio · 2024-11-04T01:10:15Z

The funny thing with the bottom row being so far off like GM is known for, you can tell your truck "ok google, how much fuel do I have" and it will give you the OBD2 percentage and will also read the estimated range before empty too. I've never understood why GM sucks at getting an accurate fuel level on the cluster. I understand filtering the data unlike the old GM trucks like my fathers 97 tahoe where you could rock the truck and make the fuel level bounce around but it should be close to accurate not this far off.

ormandj · 2024-11-04T01:13:11Z

3 minutes ago, kickass audio said:

The funny thing with the bottom row being so far off like GM is known for, you can tell your truck "ok google, how much fuel do I have" and it will give you the OBD2 percentage and will also read the estimated range before empty too. I've never understood why GM sucks at getting an accurate fuel level on the cluster. I understand filtering the data unlike the old GM trucks like my fathers 97 tahoe where you could rock the truck and make the fuel level bounce around but it should be close to accurate not this far off.

I'm baffled why it doesn't just use a percentile over time, in essence debouncing erratic polls. So 95th percentile over the last 10 minutes or something. Clearly the "miles remaining" is updating like this, I'm just at a loss for why the fuel gauge isn't, since the data is obviously there.

It sounds like this is a "known issue" and not unexpected, then?

Edited 22 hours ago by ormandj

64BAwagon · 2024-11-04T13:14:46Z

12 hours ago, kickass audio said:

The funny thing with the bottom row being so far off like GM is known for, you can tell your truck "ok google, how much fuel do I have" and it will give you the OBD2 percentage and will also read the estimated range before empty too. I've never understood why GM sucks at getting an accurate fuel level on the cluster. I understand filtering the data unlike the old GM trucks like my fathers 97 tahoe where you could rock the truck and make the fuel level bounce around but it should be close to accurate not this far off.

I was told a long time ago by someone at GM that the gas gauge hangs near full longer than it should to give people the perception that they are getting better MPG than they actually are. It seemed to make sense. They do have a habit of manipulating gauge response. The temp gauge in my POS 2005 LLY duramax would show 210 degrees all the way until it got over 240 and even then it would still show much less than the actual temp.

ormandj · 2024-11-04T13:38:24Z

That's so annoying, I just want a gauge to read accurately. Is something like the Banks idash the only good option to solve for this in a way that doesn't require looking at your phone?

KARNUT · 2024-11-04T13:50:06Z

20 minutes ago, 64BAwagon said:

I was told a long time ago by someone at GM that the gas gauge hangs near full longer than it should to give people the perception that they are getting better MPG than they actually are. It seemed to make sense. They do have a habit of manipulating gauge response. The temp gauge in my POS 2005 LLY duramax would show 210 degrees all the way until it got over 240 and even then it would still show much less than the actual temp.

You trigger a memory. Back in 1974 I was driving my father’s 1974 Ranchero GT. My Mazda RX3 was waiting on a transmission. My future wife and I were cruising around. I filled the Ranchero. The fuel needle didn’t move for 100 miles. So we ended up in Atlantic City instead of Sea Side that was closer. I’m spending my money on games and food having a blast with no worries. I’m taking my future wife back to her house pretty broke after having a blast. 50 miles towards her house the needle reads 1/2 and is dropping like a rock. I’m not going to worry my future wife but after dropping her off. I still have 10 miles to go. I had 50 cents that gave me about 2 gallons. I ran out in the driveway of the farm where we lived. Lucky for me my father was out of town not due for a few days. The most you could get was 175 miles out of a tank. It didn’t move off of full for the first 100.

dieselfan1 · 2024-11-04T14:33:05Z

40 minutes ago, KARNUT said:

You trigger a memory. Back in 1974 I was driving my father’s 1974 Ranchero GT. My Mazda RX3 was waiting on a transmission. My future wife and I were cruising around. I filled the Ranchero. The fuel needle didn’t move for 100 miles. So we ended up in Atlantic City instead of Sea Side that was closer. I’m spending my money on games and food having a blast with no worries. I’m taking my future wife back to her house pretty broke after having a blast. 50 miles towards her house the needle reads 1/2 and is dropping like a rock. I’m not going to worry my future wife but after dropping her off. I still have 10 miles to go. I had 50 cents that gave me about 2 gallons. I ran out in the driveway of the farm where we lived. Lucky for me my father was out of town not due for a few days. The most you could get was 175 miles out of a tank. It didn’t move off of full for the first 100.

Sad.

Has nothing to do with the question

We don't care about your memories.

Offer something useful .

KARNUT · 2024-11-04T15:27:50Z

52 minutes ago, dieselfan1 said:

Sad.

Has nothing to do with the question

We don't care about your memories.

Offer something useful .

Aw did I trigger you again? I’m so sorry . Your jealousy knows no bounds. We referring to you and possibly and the mouse in your pocket. Need to take a chill pill.