[klcsmooth]

what is est and where is it located?

 

[Turbo Bill]

Code 42 -> brought on by no EST pulses at 600 rpm and above. The EST, known to GM as knock sensor module, is a module located on the passenger fender back by the antenna connection. It is the module closest to the A/C blower box. I just had the same code. GM part number 16051654 is still available. HTH

 

[MR Buick]

Turbo Bill:
Code 42 -> brought on by no EST pulses at 600 rpm and above. The EST, known to GM as knock sensor module, is a module located on the passenger fender back by the antenna connection. It is the module closest to the A/C blower box. I just had the same code. GM part number 16051654 is still available. HTH

I just ran the part# on www.gmpartsdirect.com It says GM list $85.20 ,our price $42.60 Which one of those price$ in the ballpark of what you paid?They are both more than I want to pay

 

[Steve Wood]

May not be the sensor. Why don't you do a search on this forum? I think Salvage and others have posted on how to trouble shoot this problem.