How to test a fuel gauge (tank sending unit) P0463 - GM

[@williamhinton5906]

I was a navy instructor and taught reactor operation and instrument control repair and calibration. Your instruction is on a par with naval training for the reactor controls. Kudos my friend. ET1(SS)

[@ScannerDanner]

That's awesome! Thank you so much

[@Username64870]

I never seen a great comprehensive Auto electronic guru like Mr Paul.His books and related videos are really making you a great auto tech.

[@صلاحالحراصي-غ1ض]

God has guide me to you. I can't even speak or write a comment. You are just amazing and I like your character. Recently I bought a tester and a multimeter willing to learn so I'm just a beginner 😅

[@ScannerDanner]

I'm glad The Almighty has my friend. I'll help you however I can.

[@nickayivor8432]

What do you call KNOWLEDGEABLE and SUBSTANTIAL the answer is Sir ScannerDanner Brilliant video From the start to finish loved it. Thank you very much helpful information video. Take care and have a great day Sir ScannerDanner From Nick Ayivor from London England UK 🇬🇧

[@MrMatthew1969]

I like how you are thorough, and informational. Half of my auto teachers at school give half ass answers and just tell me what to do instead of teaching.

[@benmixmaster]

I've had a lot of "HIGH END" training materials, and scanner danners training materials are "HIGH END" as well. He definately demonstraited simple fuel guage Diagnostics in this video, using paper clip at tank connector, jumpering 5 volt reference to harness ground and watching scantool voltage to go from 5v to 0 volts when grounded, proving problem to be towards tank sender unit.Glad that Mr. Danner has made this video and his book available to me and any person who may work on my car some day.

[@dazeboy79]

Thanks again Paul! Great lesson on Thermistors! I get it now!

[@gladsaxisme]

Thanks for this video I have had problems with my fuel gauge on my Integra type R but rather than showing full all the time it tends to go to empty rather quickly so I went on your channel to get the best way to go about it and I can now attack the problem with more confidence Thanks again

[@Waynestarr2]

Eric The Car Guy sent me here! You are DAMN good! Very impressed.

[@DIYautotech]

I appreciate the electrical diagnosis videos you have. I have been certified in a few different sub categories as a tech, including advanced electrical diagnosis, but none of my professors came anywhere NEAR as close as you have in making sense out of circuits & showing how the powers/ grounds are switched. I will make sure to tell all my followers about you. Keep it up for the sake of all the younger generation guys who are gonna need to tackle todays advanced vehicles.

[@fivefortyeye540i]

Just purchased the book, Really defined, well im in the first section studying stft ltft trims all this critical knowledge for the price is unbelievable!! GET THE BOOK FOLKS !! You will NOT be disappointed,

[@2jzz31]

Mr. scannerdanner you are absolutely amazing at how you simplify and explain how this things work. I have learned so much from your videos on here & am so thankful for you sharing this with us on here. Thanks again and I hope you are blessed for the work that you do to help people.

[@ScannerDanner]

Thank you Josh!

[@b.b.4448]

2binsons

[@majstorivan84]

ScanerDanner majstore pa ti si Bog! To translate it is :ScannerDanner master you are God :) your videos helped me so much in diagnosing bad wires or sensors etc.By the way i am mechanic working on Renault in Serbia for five years now.I've been so frustrated doing ohm testing that was leading nowhere.Than your voltage drop testing was like a light at the end of the tunnel.I actually solved a problem in 5 minutes that was driving my boss nuts for 2 hours.Thank you.Greetings from Serbia!!!

[@nickayivor8432]

SUBSTANTIAL Sir ScannerDanner Thanks 👍 Sir ScannerDanner From Nick Ayivor from London England UK 🇬🇧

[@mymechanicfriend6017]

Mann... TOP NOTCH ASE A6 Material Here!!! I am definitely a fan!!!

[@ScannerDanner]

Thank you so much!

[@fivefortyeye540i]

Naw man thank you!! If anyone, a diy or even season technician is passionate about there craft and want to have edge over the comp..the stuff u teach is sharp as a razor blade, really defined and simplified. I have no formal training in automotive computer diagnostic.. If I can comprehend anyone can..

[@ScannerDanner]

@DIYautotech Thank you! I really appreciate the comment and the word of mouth. Have a great day.

[@jasonparker5746]

You are a troubleshooting God! This is something that has boggled my mind about CTS/Fuel sending units for a long time. Thank you!

[@ScannerDanner]

glad you liked the video. Thanks for watching and for your kind words.

[@automobile7787]

ScannerDanner How am going to test it on dashboard my nissan almera

[@ScannerDanner]

Truthfully you don't know for sure but I think what you said about the low fuel light makes me feel better about the gauge reading accurately at the lower tank levels. It is common for gauge sending units to have contact issues in only certain places on the resistor. That's what it sounds like to me.

[@Georg1979]

Thank you for your answer. And you guessed it right. It's an Opel Vectra, so it is a GM product. ;) Oh and congrats on your APSCU's educator of the year, runner up award! I've visited Rosedale's sight yesterday. And 'was looking for information, how I could visit your school. But it seems I'll have to work for a good 5 to 7 years if I wan't to go there to be a student. You would be crying if you'd know how much I earn here in Hungary. But I'm not giving up the hope. I'd truly love to be there.

[@ScannerDanner]

yes. a thermistor circuit will not be damaged by jumping the signal to ground. and they very in resistance from car to car. 30kohms cold is just an example

[@thomasgoodman9593]

I so appreciate your sharing of your tutorial.

[@ScannerDanner]

Glad it was helpful!

[@kinoadams1721]

you are the best! am from jamaica and i watch most of your videos, if not all, best teacher i learn so much, i have so much confidence in diagnosing my car! and i am giving you credit for crank sensor bypass test, wow amazing! circuit integrity test!

[@ScannerDanner]

+romie smith thanks romie smith!

[@gilbertjaramillo8735]

Super video. Now I can attempt to diagnosis my sender on my motorhome that reads empty. Like you said, if I disconnect the wire plug at the sending unit, I should read 5v with my meter to ground. Thank you!

[@claudionorjose3640]

My name is Claudionor and I am Brazilian and I have a mechanical workshop make electronic injection repair and'm imprecionado with his explanation. I am very excited about next video where else will perfect my knowledge with them thank you

[@ScannerDanner]

+claudionor jose thanks for subscribing! you've found the right place to be my friend. enjoy

[@michaelbailey2393]

What a perfect video for what I needed. Thank you for breaking this down! I have a 2016 cadillac ats-v and the gas guage doesn't work. hasn't worked since I've owned the car. I thought a new fuel pump would fix the issue; since I wanted to upgrade the fuel system. However it didn't fix the problem. Because of this video, I know exactly what to look for now. High 5 to you and your team!

[@ejjimenez3753]

Danner thank you very much, and look at the continuity of the ground wire, 5v reference. and signal cable from the sensor to PCM all have continuity and this worries me because everything looks OK but the light does not go out and do not want to erase the code it takes to return 30 seconds. or follow all of your videos and you're definitely a great teacher I would love be one of your students

[@rehanautoelectrician5411]

You are best teacher

[@shaunsautorepairs5410]

Electrical 101...always a learning day when you have a s/d video to watch

[@ScannerDanner]

The P0452 code has to do with the fuel tank pressure sensor. It sits on top of the tank unit. These code are not related, but they do share a common ground. It is a common GM fault to have a bad float resistor cause the P0463 DTC

[@ScannerDanner]

@foxholewilly It is like that for me! It also feels like that when my students "get it". Thats why I love teaching. Thank you so much for your comment.

[@hughvanzyl549]

Brilliant explanation. South Africa

[@ericvenus02]

your good at explaining how the fuel gauge system works congrats.. and thank u for your help...

[@fredautos]

I actually love this lesson with a great case study. Thanks for enlightening my understanding

[@ScannerDanner]

check it for a headgasket failure. common problem on this model. also make sure your coolant level is full (when the engine is cold of course).

[@kasoziyasin-y1h]

Thanks very much.for your teaching.

[@YouTube.TOM.A]

So much good information my head will explode !!. just doing some review before fixing a friends fuel gauge. thank you

[@mekkibilal1372]

Thank you for your time dan

[@visittbilisi3077]

Thank you, this information saved us a lot of trouble. Great Work!!!

[@salahkebi05]

Hi, that's called a voltage divider Vout = (R2/R1+R2)*Vin. Vout is the voltage reading in the scan tool, R2 is the fuel sensor resistor and R1 is the one in the ECM....THANKS.

[@tousshong9438]

Okay! Great class. I wish my mechanic/Auto mechanic teacher at the local community college can take some lesson from your class and fix my fuel gauge right the first time...after 3 tried and finally seal the leaky gas ring cap after the works being done my gauge now reads 3/4 full after filled up worst then before the fixed which shows 7/8 full when you filled up the tanks. He's now out of idea and don't want to reopen the fuel sending unit tank again because he had to done it 3 times already. Each time fuel still leaks.

[@jajabor01010101]

Thank you so much.It's very clear to me now.Please upload more we like you teaching methods.Thank you again.

[@ScannerDanner]

If its a GM, its almost definitely the tank sending unit resistor. The fingers that would make contact with the resistor have poor contact problems and eventually break off.

[@ScannerDanner]

before condemning the computer you must check the 5 volt reference circuit for shorts to ground. watch my 3 part video on a Jeep with a no start where I am doing just that. if the car still runs and it is only the coolant sensor circuit that is being affected then you must check this circuit for a short to ground before condemning the computer

[@nancylewis7142]

Perfect, Thank You for all this info!

[@ScannerDanner]

The gauge on this is computer controlled and there may be a default position with the signal fixed at 0 or 5. Try using a resistor between the terminals to drop the signal voltage somewhere between 1 and 4 volts. This should result in gauge movement. Remember you may need to cycle the key and clear the code for the gauge to move.

[@prmayner]

Thanks for your time, I'll try that and let you know what i find. I should get the truck back first of this week but i remember when the conn. was plugged into the tank voltage was somewhere in the 3v range but the gauge read empty. Don't remember if i cleared codes and cycled key though. Looks like circuitry is working just not to the gauge. tank unit had already been replaced.

[@ScannerDanner]

OL-Fault means the system is running in open loop and is usually from an O2 sensor problem or from an overly rich or lean AF ratio. This has nothing to do with your sending unit.

[@ScannerDanner]

@JohnzCarz Great point, thank you! I didn't check the gauge on this one, I should have.

[@ScannerDanner]

@MrMatthew1969 Thanks for the comment.

[@flakdawg]

Wow!!! Thanks ScannerDanner! Great lesson!

[@mugsymydog]

Scannerdanner...I did change out sending unit which as stated earlier repaired no start condition but fuel gauge will not work. I know you told me it was the sensor after the test. On the primary pump it is a 4 wire connector ( Power, ground,fuel sens, lo ref) On the secondary unit it has a two wire just fuel level sens and Lo ref. did test as you directed and verus went to "0" on both sensors as i stated. Just trying to give as much info as possible. I have been battling this for weeks and cannot go use parts cannon. form the forums I read most people do and never fix problem including dealerships. thanks

[@epstein_slayer677]

I'm a second year auto student. I've got a 1998 chevy s10 with no dtc's, fuel gauge reads empty. All tests on sending unit are good. All tests on pcm circuit are good. I can't find a diagram for pcm to gauge in cluster. How do I test the circuit from pcm to the actual gauge? Is it on data bus? This vehicle has multiple gauges that do not work and some that do work. the cluster has been replaced. Any help would be appreciated.

[@sharmarule1]

According to my opinion, Voltmeter placed between the two resistors in series actually measures voltage drop across the second resistor (One towards the ground side)

[@ScannerDanner]

That is correct but the resistor in front of your meter will change what you see too

[@i-likemy-space7729]

Voltmeters measure differences in electrical potential between any 2 points in an electrical circuit. (Not necessarily relative to ground) Measurements can be made across any one or combination of resistors.

[@larrywoodruff7530]

I've been trying to fix the gas gauge on an old 56 6cyl. Chevy truck since 1995, still workin on it!! Lol

[@henrikloiske8572]

I have an P0460 fault code on my Ford Focus Flexifuel and the wires going in to the tank is GN/OG(Volt) BK(Ground) WH/RD and BN/RD wich i think is the signal wire and signal ground.... Has Ford the same procedure with constant +5V to the signal wire?? really need your advise ;)

[@ecwurban]

I got absolutely embarrassed on an 05 F250 5.4L gas. I disconnected the connector at the tank and did all kinds of things to the vehicle harness side. Shorted it, left it open, shorted with a 4ohm test light. No matter what the gauge wouldn't change. Except one time when I plugged in a new fuel pump module to the connector I was able to get it to read full. But then it was stuck on full. Would not register any changes. I even pulled the pins out of the dash connector and did all the tests directly to the cluster. Still no changes. It was just a basic potentiometer circuit. Power wire coming from cluster through sender and back to cluster. Nothing else on that circuit. I kept doing similar tests over and over to try and find a mistake in my earlier tests that showed it actually was the sender. I so totally did not want to call the cluster! Getting it fully rebuilt would be $500 our cost... It was electronic and everything else on it worked. We dropped the cluster off at a repair place that said it worked fine. When I picked it up I found out they just moved the gauge via CAN bus messages and didn't actually touch the sender pins that went into the dash. Could there be a bad solder joint from those pins to the cluster module? I hated everything about it. We got a used cluster and of course it didn't make any difference. Long story short I finally found some good documentation on the system that mentioned the gauge operated on a default anti-sloshing mode. Unless you did this specified procedure involving pulling three fuses, cycling key, waiting, plugging back in, etc that it could take up to an hour to register any change... So it was the sender after all. The cluster WAS seeing the changes it was just IGNORING them!!! I kicked myself over that one....

[@ScannerDanner]

+E Urban oh man, I've been there with the anti slosh modules on Fords. That is something you'll never forget. I'm sorry I didn't mention that variable in this video.

[@ScannerDanner]

these two gauges have NO direct wiring to sensors, information is shared on a data network. check the fuel level sensor and coolant temp. sensor readings on the engine computer data, if they are good there and not on the cluster, you have a cluster problem

[@HectorsCarAudio1]

Man your videos pump me up !! Awesome video and info Danner !!!

[@johnnymalicoat754]

Hey paul. Why is the the fuel gague sending unit only 2 wire instead of 3 wire like every other sensor?

[@ScannerDanner]

Go to my website listed on my channel page. I cannot put the link here, but it is scannerdanner d o t c o m. If you have any questions fill out your info on my website and I well get back to you. Also watch my video about my ebook on my channel page. Thank you !

[@fivefortyeye540i]

Most would have called it whit out verifying. That's putting the T in Technical / Technician amazing!

[@prmayner]

getting truck back tomorrow, will update. No issue with cluster on 09's as far as i'm aware.

[@jamesh6922]

Hello, ScannerDanner, great video, I am getting a P0462 error code in my Lincoln Navigator 2006. my fuel gauge seems accurate with the gasoline in the tank. no gas gauge issues but my check engine light stays on and I cannot pass the state emission test.. when I check with a OBD2 scanner, I have got the Fuel Level Input (PLI) value to 0, I was not able to read the voltage of the Fuel Level. Also the P0462 states Fuel level sensor A circuit low imput, What is the sensor A mean here? is there a sensor B somewhere there? thanks!

[@mugsymydog]

Paul having problem with 2004 Cadillac CTS. Had bad fuel pump no start condition, replaced pump vehicle now runs. Fuel gauge will not operate. Wiring diagram indicates one of the wire is a "LO REF". Could you tell me if that is a ground for sensor signal and if it is supposed to carry voltage. Both fuel sensor wire have 5 volts. it also has another sending unit because it is a saddle type tank. I just do not understand what a "LO REF" wire purpose is. Thanks

[@ScannerDanner]

Low reference is the sensor ground my friend. If you have 5, 5, and 0 on a 3 wire sensor, you most likely have a bad sensor. (Sensor plugged in and backprobing)

[@mugsymydog]

@@ScannerDanner Thanks for the reply. I followed your video to the "T" . This Cadillac has a saddle tank with a sender in each side. When I take the paper clip to the wires on both side scan tool fuel volt goes to "0" which per your instruction would verify wiring is good. However I get code for High voltage on fuel level sensor 1, fuel sensor 2 and also A/C pressure sensor which has high voltage code, All of these sensors share the lo reference wire I asked you about. Another strange thing is when I unplug both fuel level sensors the Verus still reads tank is 64% full when it should read 0 because there is no input or output with wires unplugged. I may have a probem with the ECM but I am stumped. Thanks again for your time.

[@trekvana]

no need to watch again, i think i got it now. the voltage was fixed at 5 volts. then you jumped the signal wire to ground (with connector still plugged in) and it dropped to 0 volts. so you pretty much provided a different path to ground thereby bypassing the resistor in the sending unit (since current will flow through the path of least resistance). is that right? also what do you mean by pans when you said "jumping the 2 pans". thanks

[@ScannerDanner]

to be honest with you, I do not remember. I think I remember the signal voltage being fixed at 5 volts. and if I remember correctly, I wasn't doing a bypass test I was checking signal circuit integrity. so with the signal voltage fixed at 5 jumping it to ground would be the same thing as jumping the 2 pans together. maybe I need to watch it again when I get time to answer you better

[@alwayslearning6355]

Replied by bikeril on topic 2018 gmc sierra denali - P0449 code. Just checked each port to ground: red wire reads 12v constant (venting and not venting) white reads 3v when venting and 0v when not venting From the scannerdanner forum. I wonder how we have 3v on the control wire when the solenoid is not commended on? The poster finds some resistance in the control wire. No current flow, no voltage drop.

[@ScannerDanner]

Solenoid is open and you're reading a bias voltage coming from the ECM through the control circuit. kzbin.info/www/bejne/h2m9qKuAjtCMpMU

[@PhunkyNomad]

Can I use this wiring diagram for a 2002 chevy blazer . 4.3 l engine ?

[@felplayvina]

Mr Danner so every thermistor can be jump it without damage the circuit, but thermistor on cars be always 30.000 ohms cold? or can be variable?.

[@TheMattMan4494]

Great instructor!

[@ScannerDanner]

@fivefortyeye540i Thank you very much for the comment on my book! I owe you one for that.

[@mrwashur1991]

I’ve got a 95 k1500 base with a gauge that’s stuck way past full after a new sending unit. Suspect bad ground or bad sending cable to gauge. Does this year work directly off sending unit or does it pass through ecm first?

[@ScannerDanner]

I think a 95 the sending unit works the gauge directly

[@boybravo689]

Is it applies to the potentiometer sensor that method Sir

[@trekvana]

hehe. got it. thanks for the taking the time man. appreciate it. happy new years!

[@andyfanshawe]

Hi Paul. Fantastic channel here. Very talented. Very jealous of your equipment! I am in the UK but lucky to own a 97 Lincoln Mark 8 with an erratic fuel gage. Tank sender been changed but is still erratic. Ford NGS shows 0.32V in Pids but at connector under the car is 2.1V? Supposedly sender transmits to message center, then goes to the instrument cluster via the network. Gage is driven fine from the scanner, although at 80% on scan tool, gage is reading full. No codes. Any advice?

[@ScannerDanner]

@majstorivan84 That is awesome friend! I almost never use an ohmmeter anymore. In fact more times than not the ohmmeter will lead to misdiagnosis. By the way I have Serbian roots on my moms side. It is a small world isn't it? So greeting to you too from the US. A country full of mutts :)

[@cristianjuarez8150]

Greetings, thank you for all your videos and information. Can you please elaborate on this comment? Why not use ohmmeter and how it leads to misdiagnosis? If you have a video on this already my apologies. Thanks!

[@ScannerDanner]

@@cristianjuarez8150 Here you go, best example that I have kzbin.info/www/bejne/g5TWf4KAq8ljl9E

[@henrikloiske8572]

If i have the correct info it seems that the Instrument cluster in my Ford Focus controls the fuel level sensor...i am beginning to suspect that my Instrument Cluster is the culprit ?? i had 0 Volts in both the WH/RD and the BN/RD cales...and the display in the IC says Fuel computer data error ??

[@trekvana]

Paul, to do the bypass test u said we need to disconnect the sender and jump the two wires. But to check the ground you said we need to leave the sender plugged in. The problem is i didnt see you unplug the connector for the bypass test. Was it unplugged for the bypass test and then plugged back in for the ground test?

[@JohnzCarz]

In a pinch, can you use the vehicle’s own fuel gauge as the indicator of wiring integrity (instead of the scanner reading 5v/0v) when shorting the sensor signal and ground wires or does the diagnostic code cause the gauge to stop functioning until it’s cleared?

[@chotuusian4127]

Good work

[@josemontes9050]

You can have another variable it could be a short from another 5v line to the fuel pump signal.

[@alexdiosdado3736]

What you mean another variable

[@odongohenry4863]

Yes Paul I like your content absolutely but a quick one can't we have a problem between the computer and the guage? in this scenario

[@whitetiger8652]

Enjoyed the video Paul.

[@s10rider07]

i havent tried checking the sensors yet, but i have tried replacing the cluster with the original and it did the exact same thing....

[@bmb1455]

I have a very odd issue with my express van currently. ive gone through every diag in the book (that im aware of) Send wire has 5v, ground is good. multiple brand new sending units, same error. if i operate the float outside of the tank, all gauges work properly. as i am lowering the pump into the tank, all is good. shows correct level and voltage. as soon as the pump is fully seated in the ring, the gauge defaults to empty almost like the float is being held down. i have had my arm in the tank, no obstructions. any idea what i might be missing? when the sending unit is mounted in the tank the voltage says around 2.5v but operates from .7 to 2.5 when sitting outside the tank not submerged. grounds are good, ive had this same issue with 4 diff ecms, 3 pumps, 3 clusters, 2 different wiring harnesses. only thing that has never been swapped out is the tank itself. i even tried running my own ground straight to the tank.

[@nojokeauto]

nice video, question tho, does DC electricity flow from positive to negative or from negative to positive?

[@canspol]

that's a nice lecture..... Nice Video

[@ScannerDanner]

@Bushougoma Great point. Thank you

[@elisio0416]

You're awesome 👌

[@ScannerDanner]

hmm, 3v should have shown you something on the gauge. Did you search iATN knowledge base yet? To see if the cluster was a common issue?

[@Turbotomass]

awesome. "your done you need X" I love it.

[@Impedancenetwork]

What is that software and equipment (projector) are you using to project the computer screen and sense where you are writing. You seem to be using a special pen that allows the computer to sense what you are writing. What is all that?

[@pabloarevalodelaguila8767]

Excelente explicación, realmente eres bueno en lo que haces.

[@oscarrojas4281]

You are the best man

[@BELHORIZON31]

Got an issue with ethanol about fuel floater reading, any idea ?

[@saulrojas8659]

this video my be work for me again thanks dann.

[@boybravo689]

Sir where is the connection of the light that goes to the instrument cluster

[@ScannerDanner]

Thank you very much!

[@brohdyknopp613]

Do you need to make current flow throw the ground in the computer or can I just pull the signal to ground instead up jumping them either way the voltage will change on the. Signal but will it be ignore because there no activity on the sensory ground

[@ScannerDanner]

you can pull the signal wire itself to a direct ground to look for a change. The reason I used the sensor ground is to test the integrity of that circuit too

[@brohdyknopp613]

@@ScannerDanner yeah I didnt think of it that way thanks this help out a lot would eletric theroy book help with question like this Also in the middle of at series circut should the test light light. Regardless of being on postive or neagtive because there a voltage differencebetween either 1

[@ScannerDanner]

@@brohdyknopp613 depends on the resistance of the test light and the other resistor. Great question! Example: (incandescent test light being used) An ignition coil primary (coil -), test light connected to ground, key on, the test light will be just as bright as coil positive. Why? Because the coil primary winding is super low resistance. 2. Same test on a relay coil winding and the test light is very dim (high resistance in a relay coil) So 1-2 ohms on the ignition coil compared to 80-100ohms on a relay winding. Does this make sense?

[@brohdyknopp613]

@@ScannerDanner yeah this make sense less voltage being used up on the 2 ohm then 80 to 100 ohm. And with enought resitance it wpuldnt like at all .. Is this the right way to think ?

[@ScannerDanner]

@@brohdyknopp613 yes sir, from the first resistor standpoint! Then the second resistor (your test light), think of it as either causing psi to back up, (voltage rise) or flow through (voltage drop)