TPMS issues

vipergg

Well-Known Member
#1
Have a 08 Ascender and was driving down the highway and the tpms light starts flashing and after a minute went solid . Took it to mechanic and for some reason their tool could not read my one and half year old GM tire sensors. Just replaced a little while ago. So they replace 2 with whatever brand they use and then they couldnt read the other two so they replaced those too . They reset the sensors and on my way home light comes back on with the same indication , have no DIC on this vehicle . So I take it back they do a relearn again ,light goes out and they can see all 4 on their tool, Head home and same thing starts flashing then goes solid . I decide to do the manual reset where you let air out and that seems to take . Take it out and about 10 minutes into the drive light comes back on . At this point I dont think its sensors so what might it be ? The LCM gone flakey ? These systems are ridiculous, wish they could just turn it off . Not sure it is worth spending on a new LCM if thats the issue seeing vehicle is 10 years old and has 125000 miles on it . Just annoying having that bright yellow light on . Is there a way to just reset the LCM by pulling a fuse or something without killing the battery .Advice appreciated.
 
#2
Yeah, pretty stupid just having a light. However, having it flash and then go solid means a problem with the system, not a low tire. Maybe a high end scanner like a Tech 2 can tell what exactly is going on.

Maybe brand or type of sensor has something to do with it but funny it was working fine for 1+ year and then fails and keeps failing. Hope it isn't the LGM.

Found this in GM-SI if it can help.
 

Attachments

northcreek

Well-Known Member
#3
One member a while back was having nightmares with his TPMS. Eventually traced it to recently installed LEDs on his rear bumper. just sayin'...
 
OP
OP
V

vipergg

Well-Known Member
#5
Yeah, pretty stupid just having a light. However, having it flash and then go solid means a problem with the system, not a low tire. Maybe a high end scanner like a Tech 2 can tell what exactly is going on.

Maybe brand or type of sensor has something to do with it but funny it was working fine for 1+ year and then fails and keeps failing. Hope it isn't the LGM.

Found this in GM-SI if it can help.
I'm leaning towards a LCM problem. Not sure im going to invest that kind of money after chucking almost $300 in sensors and not fixing the issue. Have checked most of the common stuff . Looked at the wires at the hinge , they look like brand new . No broken stuff that I can tell . If I knew what fuse controlled the LCM I might reset it that way . Everything on the car is stock , no fancy lights have been added . Just looking on the internet just amazes me how many people have issues with these stupid things. They ought to rescind that stupid regulation . Maybe if the light is on long enough it will burn out ! :2thumbsup:
 
#6
It's an LED so most likely won't burn out. I would suggest opening the cluster and covering that LED with black tape.

Btw, it's LGM (Lift Gate Module). Wire can "look" fine but copper strands inside the insulation would be broken. You have to pull on the wires to be sure they're good.
 
OP
OP
V

vipergg

Well-Known Member
#7
Anyone know what the LGM does ? Is it only for tpms and RKE ? If so I may just pull those 2 fuses as I don't have RKE anyway .
 

northcreek

Well-Known Member
#8
I can't believe that an 08 anything doesn't have Remote Keyless Entry.
 
OP
OP
V

vipergg

Well-Known Member
#10
Rear wiper, rear lock, possibly defroster too. The schematics in the manuals should show that.
Guess thats out if it controls all that too . Maybe just try to reset it and see if I can get it to sync the sensors again . Otherwise I'll have to live with it the rest of its days . Not going to invest three or four hundred bucks on a LGM .

I can't believe that an 08 anything doesn't have Remote Keyless Entry.
Yeah believe it or not this was a low end Isuzu model and I verified thru the build codes in the glovebox it does not have RKE , stupid on GM's part seeing the car has power windows and locks to begin with . Bu then again I bought it in 2010 with 3000 miles on it for $17000 when the original list on it was $27000 brand new so I got a good deal at the time . Oh and it doesnt have power mirrors either , I really like that one . I knew all this going in though .
 
#11
Mine is also p!ssing me off. Light came on solid this morning and went out during the drive. No idea which tire or sensor. Tires looked fine. Without a DIC, this system is useless. Sensors are 11 years old so would not be surprised if they are on their out. And if the light doesn't stay on, I can't even scan it with my Tech 2 :mad:
 

m.mcmillen

Gold Supporter
#12
Autel makes a pretty decent TPMS tool the model I have is a TS401. It works very well for activating sensors when you're doing a tire rotation. You don't have to let air out of the tires to relearn the tire positions. This tool will also tell you the battery level of the sensors so it would help you with diagnosing if you have an intermittent TPMS warning light coming on.
 
OP
OP
V

vipergg

Well-Known Member
#13
Well i'm cautiously optimistic . I pulled fuses 3 and 19 under the rear seat for like 3 or 4 minutes . This resets the LGM . I then took it on like 35 minute drive and the tpms light never came on and that was a lot longer than before when the light would come back on . So we will see after driving it for a couple of days . I didnt even do a relearn . I figure whats the use seeing that I only have a light and not a DIC showing the 4 tires . Yes if I have an issue they might not know which is the problem sensor. I may just have them relearn it the next time I rotate the tires . Fingers crossed .
 
OP
OP
V

vipergg

Well-Known Member
#14
Well I believe this thing is fixed. Driven it about 40 miles and it has not come back on . So if you having issues trying to sync sensors or it isnt working right the first thing to try is to hard reset the lift gate module by pulling fuses 3 and 19 under the rear passenger seat for about 5 minutes . Once I did this I didnt even have to sync them as it saw all 4 apparently . If you have a DIC that shows the 4 wheels then you should do a relearn so it knows what's where.