Couple issues with 04 GTP you might be able to speed up process on.

[TwiztdWun]

Just got the car and there are a couple issues I want to resolve and thought you guys might have ran across these and can help speed up the diagnoses rather than me pulling out a multi-meter and hunting all over the place:

1: Cruise does not work. Have rear brake lights and fuse is good. Any other typical issues with these?

2: Fuel gauge reads erratic. Shows full when its not....shows empty when full....etc. Makes no difference if car is parked on incline or not. Thinking sending unit is acting ,but, wanted to see if there was a known common issue.

3: DIC keeps saying " Check Tire Pressure " when all tires are the same PSI.

4: DIC says to service Variable Effort Steering.

5: I seem to not be able to turn TC on/off. Wondering if 3,4 & 5 are related.

6: Typical HUD spring unhooked. Got to get that fixed.

 

[Scottydoggs]

gas tank level sensor is bad.

and its probably best to get the other stuff scanned, see wtf its all yapping about.

 

[Fivefingerdeathpunch]

2. Level sendor/sensor, the fingers on the circut board have worn off. Dorman makes a replacement part and being an 04 likely still has the access panel in the truck. It was taken away somewhere through 2005.

3. I think there is a relearn procedure that can be done, even though it has no real tire pressure sensors in the wheels themselves.

4 and 5 are likely related to each other, but I can't be for sure on that.

 

[nik12937]

I have a feeling 1, 3, 4, and 5 are related. In 04 and 05 models, the tire pressure is monitored using the wheel speed sensors. The tire pressure will affect the wheel speeds, and once the BCM notices one wheel consistently moving a certain degree slower or faster than the others, it will ask you to check your tire pressures.

When a wheel hub (and therefore it's wheel speed sensor) begins to fail or has an issue with its wiring, the readings can become inconsistent/erratic, and this can cause the PCM to disable the ABS system, the TC system, the variable effort power steering, or any combination. If any of those systems are having trouble, the PCM may not allow the use of cruise control.

Your best bet would be to get the vehicle scanned for stored ABS/TCS/cruise control codes as not all of them will actually set the MIL. I personally had issues a year back with my cruise control not always activating, and sometimes disabling itself while cruising for no apparent reason. A month down the road my rear-left wheel hub started making noise and set off the ABS and TCS lights. My guess is a wheel hub or its wiring could have issues, and if so the stored codes will at least point you to which wheel is being affected.