20 Most Recent 2001 GMC Sierra 2500HD - Page 7 Questions & Answers

NOTE:The transmission is on the same fuse as the MAF, O2 sensors and at least one other sensor - if an O2 shorts out, it will blow the fuse and the trans will go into limp-home mode. Be sure the trans has power and the fuse is not blown before doing anything else.

Also note that many problems that show up as transmission issues are actually PCM or electrical, and may be external to the transmission. Try a different PCM, and check for chafing where the cables come out of the PCM.

Secondly, put a line pressure gauge ($55 shipped on Ebay, or visit a local trans shop) on the pressure test port and go for a drive to verify proper line pressure. Base pressure at idle in P,N,OD should be around 70psi and around 140psi in R. Max line pressure should be at least 190psi at WOT in 1st or 2nd, 225psi is optimum. If base pressure is low, trans or pump is worn out. If max pressure is low, check EPC solenoid. If reverse is slow to engage, and line pressure does not come up to at least 130psi in reverse, replace the boost valve with a Transgo 0.500" boost valve (easy fix in pan).

What is "limp-home mode" ? This is a fault mode in which the transmission either loses electrical power or the PCM deactivates all of the electronics. The transmission will default to max line pressure. The driver will have Reverse and 3rd, with manual 2nd available by putting the gearshift in 2 or 1 (doesn't matter). 1st, 4th, and TCC lockup will not be available. It will not hurt the car to drive it like this for short periods, but use manual 2nd to get the car moving, and be aware that the trans will generate more heat than normal while operating in limp-home mode due to increased torque converter slippage during 2nd gear starts and no lockup in 3rd gear.

Trans shifts into gear harshly, car feels sluggish off the line, No 1st, 4th or TCC lockup available, Manual 2nd, 3rd and Reverse are only available gears, CEL is on: Transmission is either in limp-home mode or has lost electrical power. If there are lots of error codes in the PCM, check the fuse that powers the transmission, and if it pops again, look for a short in that circuit like an O2 sensor harness touching exhaust. Otherwise, check PCM codes for a particular fault in the transmission causing the PCM to put it in limp-home mode.

Car goes into gear but feels very sluggish like the brakes are dragging, but it will roll easily (starts out in 4th gear), you manually shift to 2 to get it moving, once it's moving you put it back in OD and the car shifts 3rd to 4th on its own and locks the converter at the appropriate time: ShiftB solenoid failed: Easy fix in the pan. Or a wiring problem from PCM to trans.. or PCM.


Start with the simple things and check the fuse and Wire leads at the ECM's Transmission control module and the transmission it self. Look for any damages to the wire harness and leads. Try disconnecting the wire harness form the clip on the transmission and cleaning it with brake parts cleaner and reconnect and pull the Fuse to the ECM with the ignition on the on position "engine not running" for 10 sec and place back in and start the engine and go for a test drive and see if that reset the transmission. Good luck and keep me posted, we'll get your transmission running 100% again soon.

the fuel pump is inside the fuel tank. some techs just lower the fuel tank down, others remove the bed. personaly dropping the tank is harder, but lifting off the bed requires about 4 strong people.

not sure here but i would hazard a guess that the operating solonoid is weak

You will need a diagnostic scanner to see whats going on. There is no other way fiqure this out.

If there is not a small cover that snaps off from the center of the crank with a screw behind it, then they are simply "pressed" on by machine. The only way to remove it is to keep prying at it from behind while trying not to damage it or the surrounding door panel. Good Luck.

Hello tsundw.
Gray(positive from relay) and black (ground) are for fuel pump.
Purple and Orange are for your fuel level gauge.
That is a diagram for the gasoline engine.
Hope this helps you solve your problem.

Hello,
It sounds like you are describing the A/C fuse.

I hope this helps.

Roy

same here bro on my gm. if the noise is heard just for the first minute or so, no big deal. try putting in some engine restorer, before you do an oil change, one that says it removes gum from sticky valves and piston rings. i use wynns. follow instuctions on can.

The code should be p0093. It is for an injector(s) problem. It usually means that there is a problem with the injectors where the fuel is leaking internally back to the fuel tank or into the oil pan. The injectors had a warranty of 200,000 miles or 7 years for this problem. Unfortunately you are over by years.

its probably on the back of the inside fuse panel on the driver side. usually looks like a metal cylinder or a black plastic square box. all it is is a relay. should be easy to find.

check all the fuses. if used alot it will pop the fuse. should be i think is 15 or 25 mini fuse. best of luck

get free scan at autozone for fault codes. Maybe dirty mass air flow sensor

the fuse is located in the underhood fuse block. if you remove the cover & turn it over there is a diagram that tells you which fuse is for what.

side fuse panel, I am not sure but I thought that it had a breaker so that it should reset.

sounds like the abs needs servicing

The vibration is coming from your rotors. You can either replace them or have them miked to see if they can be turned. For the left to right play you should jack it up and check the lower and uper control arm bushings as they might have osme play in them as well. While you are there u will be able to see if the wheel bearing is loose, you will be bale to fix that when you do the rotors. The brakes lights are from low fluid or faulty Abs sensors that are attached to the front hub, this will be easy to see as the only wires running to the hub right behind the rotors.
Heres hopping that thouse rotors can be turned :)
good luck

TURN ON THE IGNITION WITHOUT STARTING THE TRUCK, AND FULLY DEPRESS THE ACCELERATOR THREE TIMES WITHIN FIVE SECONDS. TURN OF THE IGNITION AND THEN START. THIS SHOULD CLEAR THE MESSAGE. IF IT DOESN'T THEN REPEAT. HOPE THIS HELPS. LET ME KNOW. THANKS FOR USING FIX-YA.

No, have you changed the spin-on filter om the transmission yet? This may be the only trouble. I hope this helps. Good luck.