20 Most Recent 2003 GMC Yukon XL Questions & Answers

What size engine ? 4.3 L vortex P0300 random misfire code is usually associated with vacuum leaks , but could also be low fuel pressure , plugged fuel filter , fuel pump problem , clogged injectors etc... doing fuel pressure an flow testing would confirm or eliminate that as a problem . Fuel injector balance testing would confirm or eliminate clogged injectors .

i have same issue here 2003 yukon

The player can't read the disc

This is a follow up to the problem I posted. (Like many others out there). Guess what.... there is NO RECALL on the Memory Control Module Computer for the seat heater controls. Sorry, no freebies on this one. There is a TSB (Technical Service Bulletin) from GM that advises the repair shop (dealer) to investigate and install a new MCM (Mem Control Mod. So, sorry, there's no fix except to replace.....at your cost. But, I have good news! The GMC dealer only wants to charge us $495.00 for a new MCM! Isn't that great news! Uh.....no, it's not. I did, however, find that Ebay carries a stock of them (and a particular vendor that only stocks GM products). Ebay inputs them as "door switches", so be sure to look for your year and model with "door switch" as your search term. The vendor that supplies them on Ebay, and at their store front, is called "G and R Auto Parts" from Oklahoma City, OK. They only deal with GM used parts, and I found mine for $50! What a deal! I just installed mine and it works great! I called down to talk with them and they are great to deal with. Read on if you want to see the technical side of the repair.....

I consider myself a "weekend warrior" with computers and light mechanic work on cars, so I did my own diagnostics on the car to find the specific issue that caused the seat heaters to freak out. There are 2 computers that control the seats. One is located under the drivers seat in a black box about the size of a 5x7 picture frame (1 inch thick). The other computer is located under the window switches on the drivers door. Actually, the switches and computer are all one unit. The computer boards in this "switch box" control multiple things that I'm not entirely sure about. I do know this..... The green plug goes to the switch box for the seat memory/seat heater/ pedal memory. That's as far as we needed to go. With the standard varation control that we all learned in chemistry class to add/subtract one variable at a time, we deduced a couple of things. 1, the computer circuit board was reaching in excess of 330F degrees! We got the temp reading from an infrared thermometer for $15 at Radio Shack.(Good purchase!) I don't know much, but that can't be right. After we played around with that for a minute, we were able to tell that a certain computer chip was getting too much juice and it created jumps and skips in the controls that made the seat heater come on and off. It also got so hot that it initiated the windows and mirrors to do crazy things. Wild stuff! Then, we looked closer at the circuit boards..... there were a few burn marks by some resistors that just happened to be hooked up to the Green plug. Ahhhhh, the plot thickens. After that, we investigated a few more areas on the board and found that there was also a little corrosion around the green plug. Bingo! We theorized this..... Because the com chip got so hot (We don't know why, it's only got 81,xxx miles), the chip send a power surge to the green plug resistors. It burned out the resistors, thereby creating a dam for the power to go nowhere except burn the chip faster.(330F+) This initiates a powersurge in other areas and created the voodoo ghost effect of the seat heaters going on and off (And later the windows and mirrors). Because the chip burned the resistors, it burned off the protective coating that is applied to keep moisture out of the circuits and solder. This created the corrosion and possibly even more problems, but hey, it only took one time to see the effect. Crazy huh?!?!?!

There it is..... My theory and my fix. Hope this helps. As always, please contact me anytime if you have any problems.

Thanks and good luck.

Brandon
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sounds like the clutch assembly for your A/C unit is toast!! thats why the belt broke, Hopefully its not the whole unit seized,, that gets expensive !!

Actually,you both could be right.It may be the bearing inside the compressor.The compressor does not make the cold air,it helps pressurize the system to get the freon from the evaporator to the condenser.The evaporator provides the cold air.If you can,open your hood and have someone start your car.Have them give it some gas and see if you can pinpoint the noise more accurately.If your compressor bearing causes it to seize up,you will probably only get a couple of miles before your belt snaps.Another slight possibility is the tensioner.It's pretty rare but stranger things have happened.I did have a compressor seizure years ago and snapped a belt though.If you can pinpoint the noise it would help to know.If you can't I would like a better description of the noise though.Good luck! Greg

I have a GMC Yukon XL 2003 and I need to know what this part is. Can you help me

Does fuel pump run ? Remove fuel cap. Have someone crank it for you,you should hear fuel pump running. If not bang on bottom of tank while cranking. If it starts fuel pump will need replacing , if not check for power to pump, if it has power,replace pump. If no power, check relay for operation

I suggest you get one of those manuals people get nowadays to do it yourself.. My brother used it to repair my car and it's totally repaired now. he got it from. www.reliable-store.com

you replaced check the electrics but forgot the obvious bad injector , connections and fuel pressure

chances are your brake pads are in need of replacement(auto wear indicators)

2003 gmc If you're finding it difficult to service/repair your car, get one of those online manuals. You'll not have to wait for others to answer, or rely on mechanics and all. Plus i know a website that sells very cheap but very very good manuals online, without expiry i.e. for lifetime.

not sure if you did all these steps but maybe it'll help.... https://northcoastkeyless.com/2003-gmc-yukon-denali-keyless-entry-remote-programming-instructions/

It sounds like you have a bad connection on the battery. Make sure to clean the connections, make sure they are tight, and make sure the ground cable has a good connection at both ends, battery side and body/frame side. The bad connection is the only answer when the battery is fully charged and you turn the key and it all goes out. If you can turn on your headlights and press the brake at the same time, and they work, then it may be something else, but I would be amazed if they do work given your description of your problem.

So, make sure the battery is charged and clean and tighten all your connections. Test battery connection by putting it under a load with all the lights, head, and brake at the same time. If it goes off then, redo cables again.

Good luck.

2 wheel drive or 4 X 4 ? Automatic or manual climate control Do you know what DTC'S - diagnostic trouble code's are ? DTC B1375 The ignition 3 voltage circuit is a discrete input to the HVAC control module. The HVAC control modules uses the input to determine that the ignition switch is in the RUN position. When the ignition switch is in the RUN position, ignition voltage is applied to the input. Rather then guessing as to what the problem , not being able to diagnose properly , your best bet mite be to have a qualified repair shop check it out . Would need to hook up a professional or factory scan tool to check code's ,see if the climate control module will communicate with the tool . HVAC Control Module The HVAC control module is a class 2 device that interfaces between the operator and the HVAC system to maintain air temperature and distribution settings. The battery positive voltage circuit provides power that the control module uses for keep alive memory (KAM). If the battery positive voltage circuit loses power, all HVAC DTCs and settings will be erased from KAM. The body control module (BCM), which is the vehicle mode master, provides a device on signal.

Look for a chaffed wire in the hinge area of the driver's door. That's the most likely place to find a short or break

you have a leak in your mass airflow hose the big one

What's your question ? Tailgate ajar light lit on the instrument cluster ? The Body Control Module (BCM) monitors the lift glass and the cargo door ajar switches. When the switch closes, the path to ground is completed, and the BCM sends a class 2 message to the instrument cluster to display the CARGO DOOR AJAR message.There are two ajar switches for the rear door ,a left an a right ,the third switch is for the lift glass ajar switch . All three of these switches splice pack SP410 At ground point G410 (Shouldn't have any readings when door(s) and/or window closed.) It's the opposite . switches are open with door closed , G410 In the Body Harness, Behind the RR quarter trim panel near the D-Pillar It turns out it has nothing to do with rear door. Something about drivers door actuator. NO IT DOESN"T !!!!

Check all fuses in your power box. Sounds like could be electrical short. Check connections and grounds to alternator and starter and battery. Also check coils, plugs etc.

Once resolved, try a can of SeaFoam from Canadian tire $12.00..put half in a full tank of gas and the other half in your oil. Do this when the engine is warm, not hot. Let it sit for 30 minutes then take it for a 10 minute drive and see the difference. Save hundreds in injector flushing. This should alleviate the hard starts.cheers.