Denali P0172/P0175

[dallasz71]

Recently purchased a 2010 Yukon Denali, 138k. Ran great, near perfect condition. The temperature really dropped last week, and one morning it threw several codes. P0101, P0172, P0175, P0446. Initial cold start is rough, sometimes dies. Once it's warm, runs completely perfect.

I replaced the MAF, cleaned the throttle body, and seafoamed the upper intake. I did notice around a 2" puddle of oil (looked a little milky oil looks fine) directly under the breather. Fired up cold, seems better but not perfect. Threw P0172/P0175, still running rich. I haven't replaced the Evap vent solenoid, but that's next.

One thing that concerns me, I filled up prior to the check engine lights and added a bottle of Lucas Injector cleaner. The check engine light came on shortly after this.

Could the Evap solenoid cause the rich codes? I have yet to have this code appear again.

Any suggestions?

 

[TheAutumnWind]

Troubleshooting P0172
Pro Tip: Before diagnosing fuel trim problems, it does one well to note that the Fuel Trim Monitor will not run unless the HO2S monitors have run and passed first. The fuel trim monitor uses the oxygen sensor to run, which means that fuel trim codes are not oxygen sensor codes.

• P0172 with P0175 or MAF DTCs – If you note both P0172 and P0175 or concurrent MAF-related DTCs, then you can likely rule out individual cylinder, ignition, and fuel injector problems. Instead, focus on the fuel injection system and the MAF.

http://www.troublecodes.net/pcodes/p0172/

Trouble Code Fault Location Probable Cause
P0172 System too rich, bank 1 Intake blocked, EVAP canister purge valve, fuel pressure, EGR system, injector(s), HO2S

 

[AngelXL]

Just in case.
http://www.tahoeyukonforum.com/threads/evap-valve-p0446.87124/

 

[GM Customer Service]

Recently purchased a 2010 Yukon Denali, 138k. Ran great, near perfect condition. The temperature really dropped last week, and one morning it threw several codes. P0101, P0172, P0175, P0446. Initial cold start is rough, sometimes dies. Once it's warm, runs completely perfect.

I replaced the MAF, cleaned the throttle body, and seafoamed the upper intake. I did notice around a 2" puddle of oil (looked a little milky oil looks fine) directly under the breather. Fired up cold, seems better but not perfect. Threw P0172/P0175, still running rich. I haven't replaced the Evap vent solenoid, but that's next.

One thing that concerns me, I filled up prior to the check engine lights and added a bottle of Lucas Injector cleaner. The check engine light came on shortly after this.

Could the Evap solenoid cause the rich codes? I have yet to have this code appear again.

Any suggestions?

Good Morning dallasz71,

Our team would be more than happy to take a look into your situation on our end and get you in touch with a GM Certified dealership. If this is something of interest, please send us a private message that includes your VIN, full contact information, current mileage, and preferred dealer. Thank you and we look forward to hearing from you.

Philip J.
GM Customer Care