20 Most Recent 2001 GMC Yukon XL - Page 8 Questions & Answers

Same question...same answer:http://www.fixya.com/cars/t12505949-po442_code_need_know_fix?eventid=21387790

First check your battery condition, and make sure your cables are tight. Any signs of leaks at the battery, green furry resistance on the terminals or loose connections, will cause your symptoms. If your alternator isn't charging, the battery light in the cluster should flicker. There are too many systems affected, the most likely common area is the battery.

The speed sensor on your trans sends a signal to the electronics telling it when to shift, this will be where you fault is.

TRY LUCAS OIL,I USED A FULL LITRE FIRST,WILL LET YOU KNOW HOW IT WORKED.BEFORE THIS I CHANGED OUT TWO ROTTEN LOOKING KNOCK SENSORS,THEN TWO WEEKS LATER REPLACED THE REAR ONE AGAIN,AND IT FAILED AGAIN.AND SO I AM NOW TRYING THIS NOTICED A BIG DIFFERENCE IN POWER NOISES,NO PINGING,NO RATTELING LIKE IT IS A DISEL.

The steering wheel needs to pulled off, there is a short somewhere in there. Better have it done, cause if it isn't done right, the air bag can deploy.

It can be a number of issues including a problem in the transfer case. But the control module no that is unlikely

If possible and there is an Autozone or Advanced Auto nearby.Take it over there and have them scan the codes for you.They usually do this at no charge and post the retrieved codes in here so we will know what type of problem we are looking at so that we may provide with the best possible solution to your issue.

First disconnect the fuel relay and start the engine and let it run until it cuts off.There is a fuel service port that is on the fuel rail.You will need a fuel pressure gauge then connect it to the service port and turn key on and read gauge.After reading gauge you can put the relay back in.

Check your fuel pressure it should be 50-55 psi.Sounds like the fuel pump is to weak.

look under the car Drivers side its like in the frame .

does it do this constently