2003 Yukon Throttle Noise

[quickhitch11]

Hi all, looking for a bit of guidance. My own vehicle, 150K on odom. 5.3L
I recently noticed while on the hiway, a clicking noise from in the dash in front of me in what i think is the upper left side. It sounds like a relay. I plugged in the Verus, No codes anywhere, ( no MIL light ). It is a fly by wire, No Cable Throttle. I drove while scanning, and noticed it never goes into closed loop. Hmmm, betting it's related?? It had been run for aprox. 30 mile trip, so all temps were up to normal. I found the clicking happens only while gas pedal is depressed, i can almost control it with my right foot. It does not happen with cruise control on. I know i have relays in fuse area on left side of dash, and am going looking at it in the AM. Did not know if anyone has stumbled on similar issue or not. I have the original 30lb shop manual, and will be digging in, in the AM. I will let you know if i find anything. As always any guidance is appreciated. thanks in advance,
Chris

[quickhitch11]

A bit of an update, while plugged in to Yukon, found no communication with ABS module. Checked fuses, all good. Do not know if it could or could not be related to throttle clicking. Still looking, have had numerous heart related health issues, so I have not been here for a while, and it is difficult getting under truck. But persistence will pay off, will continue to dig and update. Thanks again, Chris.

[Joe Rappa]

Sorry to hear you're not feeling well. i hope you mend quickly.
Any chance you could get your hands on a Magic Ear or something similar? At least it would help you verify the source of the noise.
Joe

[greasybob]

The TAC module is right on the other side of the fire wall. Never heard one make noise though. No codes and no closed loop ? Temp sensors working ? 02 bias voltage OK ? Have all monitors run ? Maybe a clue there ? Monitor all the voltages in the BCM data, maybe something there. Did someone disconnect the ABS because of a malfunction (stuck relay, or low speed activation) ?

[quickhitch11]

Thanks for the replies. Because it's my vehicle, I know I did not disconnect the ABS module. On occasion I plug in the Verus just for a look-see. Had always been able to communicate with all modules. Also, checked again, and now the loop closes upon temps comming up to normal. I thought possibly more than one coolant temp. Sensor, but according to manual, and schematic it only has the one. Should have a lift available this week. Will keep you posted. Has anyone heard of possible issue with the throttle pedal mounted unit? Thanks again, Chris

[Witsend]

I figure there's something basic like an unmetered air or fuel leak somewhere that the throttle body can't get rpm to where the pcm desires it to be ,and the PCM repeatedly is signalling the TAC (throttle actuator control)to do what it expects to see done.