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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 30535
Experience:  GM Grand Master Technician 2007. 14 years experience.
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I had a alert to clean my muffler fileter on mu 6.6 allison,

Customer Question

I had a alert to clean my muffler fileter on mu 6.6 allison
JA: How many miles are on the car? How has your MPG been lately?
Customer: 106,000 11 t0 17 depends how I drive it
JA: What is the model of your '11 Chevy?
Customer: it's 2008 Silverado 2500HD
JA: Are you fixing your Silverado yourself? What have you tried so far?
Customer: I read on line to take it for a***** turned it off and it cleared 'I went to a different place for fuel, could that have caused it ?
JA: Anything else you want the mechanic to know before I connect you?
Customer: No
Submitted: 1 year ago.
Category: Chevy
Expert:  GM Tech (Cam) replied 1 year ago.

Hi there, I am Cam.
Poor quality fuel may have caused this, but it might be something as simple as your recent driving habits. If you spend any time idling, only went short trips , both would cause it.

Considering you only reported the clean exhaust filter, the best bet is exactly what the manual said, go for a 20-30 min drive on the highway. Nothing special, just get to speed and cruise. the system will enter PASSIVE REGENERATION and ideally it will clear this message after 20+ mins driving.
Should that fail to clear it, then we might require a shop to put the scanner on and perform a service regeneration.