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GM Bob
GM Bob, ASE Master Technician
Category: GMC
Satisfied Customers: 1103
Experience:  30 plus years experience as GM technician, ASE Master Technician and GM Certified
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P0877 P0872 P0842, 2008 GMC Yukon Denali, troubleshooting

Customer Question

P0877 P0872 P0842
JA: What is the make/model/year of your car?
Customer: 2008 GMC Yukon Denali
JA: Are you fixing your Yukon Denali yourself? What have you tried so far?
Customer: troubleshooting information
JA: Anything else you want the mechanic to know before I connect you?
Customer: Had O2 sensor issue and replaced CAT system with all four O2 sensors had multiple O2 changes after initial replacement, then new transmission pressure sensor issues immediately thereafter
JA: Have you located all of the vehicle's oxygen sensors? Are the wires leading to and from each intact and in good shape?
Customer: intact. on the one reamaining (flagged on last OBD check) i checked connector and found some grease contamination. cleaned it with spray degreaser. haven't checked codes since then
Submitted: 8 months ago.
Category: GMC
Expert:  GM Bob replied 8 months ago.

Hello my name is ***** ***** I can help.

All the codes you posted are for the trans pressure switches.

Are these history codes?

All the pressure switches are part of the trans control module.

What are you trying to fix?

Please get back with me

Expert:  GM Bob replied 8 months ago.

Please let me know if you need more help.

If you can take a moment and rate my service.

Thank you