Customer Drove 8 Hours...for THIS?? (GM Truck Poor Shifting)

hey everyone welcome back to pine hollow auto diagnostics today we have a problem child chevy 2500 hd or 3500 hd with the six liter v8 and you can see frustration the owner drove it i don't know how many hours did you drive here chris okay almost eight hours from from michigan i think and he bought this truck five years ago and he said from day one it was not driving as it should first thing he took it to a transmission shop it wasn't shifting very well they put in a remand transmission it did the same thing it turned out the problem was a brake switch that was stuck so he was upset with that obviously with the new brake switch he said it drove much better but not perfect and i mean i don't know how many shots this truck has been to stuff has been replaced you see the engine computer's fresh the wiring is all untaped you can see there's oh i don't know some shrink wrap some shady repairs but let's let's just start from scratch he said there's several issues with the truck when it's humid sometimes it just loses power the tow haul mode does something weird with the transmission just do a health report here and we have a 455 evap system large leak don't care about that right now theft deterrent key and correct okay engine oil pressure sensor performance that's could be important throttle closed position performance that's that's interesting he said he could never sync up the accelerator pedal and the throttle so that code will definitely look up and we have heated oxygen sensor stuck lean bank 1 sensor 2 heated action sensor stuck rich bank 1 sensor 2. so this bank one sensor two apparently is having some issues in the transmission we have a transmission fluid pressure switch one circuit high voltage okay another cause for weird shifting uh but at least we have these codes so where do we begin let's uh first let's go to the engine control module look at the electronic throttle data look at the oxygen sensors see how it runs and you know start from there okay so just with the key on we have accelerator pedal position sensors one and two and then tps sensors one and two i'm just going to depress it see what happens all the way to the floor 96 percent and release it down to eight percent let's just start it up instead it has kind of a rough idle it's shaking a little bit [Music] okay so the throttle right now is at 14 and we're at 600 rpm usually you want to be below 10 percent so could be a dirty throttle body perhaps oh let's see here indicated angle [Music] so the app is fine zero percent zero percent on number two so right now at idle we're at 13 keep that in mind let's look at some oxygen sensor data bank one sensor one bank one sensor two think two sensor one and bank two sensor two let's also look at the fuel trims obviously long term fuel trims loop status mass airflow short term one and two so long terms are right around zero short terms are right around zero so i'm looking for oscillation on the upstreams right there and on the downstreams we're hanging out around 700 millivolts which is fine i really don't see anything wrong there gonna load it a little bit [Music] okay just look at misfire counters real quick nope no misfire counts so it seems to be pretty happy all right so out of all these codes so during this drive cycle we don't care about theft to turn key large leak engine oil sensor performance maybe later this one right here throw throttle closed position performance failed current uh i want to address this one um o2 signal stuck wrench rich bank one sensor two or stuck lean bank one sensor two again not really worried about these two for drivability these are downstream sensors so maybe we have a lazy you know downstream sensor but let's uh look up this p2119 see what the description of that code is see if we can address this one then we'll clear the codes out take it for a spin see how it drives and you know go from there okay so the two one one nine code conditions for setting the dtc the ecm detects that the throttle blade did not return to the default position when the attack motor is de-energized for greater than one second okay like i've never seen this code before in other gm trucks so the question is what is the default position and on scan data can we see this um you know when the throttle motor is de-energized with the key is just kion engine off what is that position and why is it not happy with the throttle blade not returning okay so here's the throttle body keys off right now i just want to do a visual inspection on it he said it's brand new now is it an ac delco part that's questionable and then the owner said that they fiddle around with the tps sensor they replaced that separately so unknown part quality here but this is the default position you see the the blade rests right there and that's how far it takes to close it so there's default position fully closed fully open okay so let's turn the key on and just look at the data stream for throttle actuator control and i just want this tp position sensor stuff so 12 data pids graph those so i push it down all the way we are at zero percent the default position is at 28 apparently and fully open we're at 107 percent okay so why is this thing not happy so let's see keon see we're down to eight percent if we wait a while there it is back to 28 percent key off there's your key on again play around with the accelerator pedal does go to 100 if i release the accelerator goes down to eight and back to 28. so let's see that happen here okay just went back let me tap the accelerator one more time so we're eight and bam back to 28 so everything seems to be working fine [Applause] i don't see a clear reason for this 2119 to set just yet so just for consistency let's clean the throttle body run the truck at idle see if the angle is closer to you know i don't like that 13 to 16 percent idle number so let's just clean it out and see what happens well we're down to 12 percent at idle so i'm not going to worry about that for now i want to take this truck for a spin i want to clear out all these trouble codes right now um actually before we do that let's go to the tcm this transmission fluid pressure switch high voltage last test not run see if that is freeze frame commanded here coolant that's all the data that we have emission fluid pressure tfp switch one let's look up that code before we clear anything so looking up the p0843 trouble code so these tfp switches there's one three four and five and the circuit description here is tcm supplies 12 volts on the signal wire and this switch is either open or closed to ground so the signal is either high or low so the normally high clutch pressure control solenoid 2 controls transmission fluid to the 3 5 r clutch the tcm monitor is a normally closed tfp switch one signal to determine the clutch status okay so it's like a feedback circuit so tcm detects that the tfp switch 1 signal voltage is high when the 35r clutch is commanded off so it could be an internal transmission problem not necessarily a circuit problem we can actually take a look at the live data while doing the test drive and see if these tfp switches shift accordingly okay command the shift transmission with a scan tool to achieve second gear observe the suspect scan tool tfp switch parameter while commanding the shift transmission of the scan tool achieved fifth gear each tfp switch parameter should toggle states from high to low or low to high between second and fifth gear if the parameter does not toggle perform the control solenoid valve transmission control module assembly inspection okay pretty cool okay so apparently we can do a scan tool check here to see the states of the tfp switches um without test driving it so we can do that and see if it passes that test so for any transmission related issues obviously you want to check the fluid level so truck is level riding transmissions nice and hot [Music] you guys see where that level is it's below the cold mark we should be all the way up here so i might add a quart of transmission fluid here and then you know so we're starting up with no good fluid level all right so i added two quarts of valvoline max life fluid to get the level up to the hatched area here in the hot zone so that that's quite a bit now we can clear all the codes out take it for a test drive see see how it drives so i clear the fault code out of the transmission and if we look at the data stream at these four tfp switches one three four and five so let's graph these so right now we're in park tfp switch one that was the the code for that one it's high if i switch it to r low high low high it stays high okay give it a little gas low see back in park goes to high back to reverse low high low and give a little gas all right let's just take this thing for a spin so let's go to the engine control module and just clear all these codes out as well yes okay read fault code interesting two one one nine looks like it's a hard fault let's clear it one more time okay no dtc's there it is boom so the 2119 is a hard fault well let's just test drive it and go from there all right let's uh we're just in drive let's see how it accelerates that's a second third fourth so let's slow down again do a little incline second third lock up there it is there's lock up so now let's uh try the tow haul feature so that should yeah it's definitely uh driving higher before shifting still seems to be okay so now we're going to turn left and let it go through its gears again yeah it was downshifting earlier that's good so let's see come to stop second there's third she said in third it hangs up easily there's four smooth ass butter you know i should let the owner drive it yeah see if he can get it backed up but keep in mind we put two cords of transmission fluid in this thing so that i think it'll actually drive much better with uh with the proper fluid level now that is the main customer complaint so we'll take it around the block and see if we can get it to act up or not and then we'll address any other issues maybe clean up that wiring or something but seems to be driving fine and there's regular mode all right so the owner's been driving it for about 20 minutes and what are your thoughts chris he's good at what he does it's fine it's working well it's working well with tow haul mode works fine engine braking works fine it shifts i mean shifts as well as any well-running chevy truck i've ever driven so this is the squirrel survive lucky day no dtc's in the tcm that's good so as of now the only thing we've done is added two quarts of fresh fluid to the transmission to bring the fluid level up to the appropriate level and two quarts that is definitely enough to cause poor shifting you know slipping i've seen it before many times on these chevy trucks um why would was the fluid level low well again you said for five years has been doing this stuff right i was checking it okay so the key is here that obviously the owner has checked the fluid before he goes straight um but he's doing it with the engine off that's a very common um you know mistake on some vehicles like on hondas you are supposed to check it with the engine off on most vehicles with automatic transmissions vehicle has to be on a level surface in park engine idling and then you check the fluid level so if you check it with the engine off obviously the pump in the transmission is not running and more fluid will settle to the pan and you'll think hey my level is fine but actually it'll be about an inch higher than if the engine's idling and that's enough that's about two ports right there that's enough to cause all kinds of issues so um where do we go from here that was the main customer complaint i think we're in good shape on that front if he wants me to do anything else like i don't know tape up some wiring harnesses or whatever we can do that or just let the truck go if it's happy it's happy so i think we'll leave it at that thanks all for watching and we'll see you next time

Channel: Pine Hollow Auto Diagnostics

Views: 70,185

Keywords: GM, truck, transmission, shift, slip, fluid, power, throttle, V8, diagnostics, P0843, level

Id: A-tkYBtwwbs

Length: 25min 54sec (1554 seconds)

Published: Wed Jul 20 2022