Check Engine Light

[Ron Langdon]

Ready to leave Woodland, Wa and check engine light came on! Driving 2008 Patriot Thunder with C 13 and 32000 miles. Yearly service completed at Trucks Northwest, Bellingham, Wa last week. Fault code SPIN 3556 FMI 7. Seems to be a fuel, after treatment problem. Called Cat and referred me to Peterson in Longview, but can't get anyone out until Friday! Anyone (Gerald) know of a good mobile mechanic in this area (Portland, Or). Thanks.

[Gerald Farris]

Ron,
Not being from the area, I do not know of any qualified mobile mechanics in that area. However, most mobile RV mechanics are not qualified to diagnose and correct problems with the emission systems on a Cat engine. So if you call one, be very careful about their qualifications and ability level.

Gerald

[Mike Humble]

You may try Peterson in Portland.  They are larger and about the same distance.
Mike

[Ron Langdon]

Gerald & Mike. Thanks. I have Peterson coming over on Friday morning, unless I can get him here sooner. Gerald, I especially appreciate your heads up. The mobil tech that came out this afternoon was good intentioned, but he didn't tell me anything I didn't know or hadn't learned from Cat. We did reset the fault system and the fault did not appear after restarting the engine. What I don't know is was the fault a failed test since it didn't appear after reset or is it something more (bad/clogged jets, for example). If I drive the coach and the fault doesn't appear, am I damaging the engine. Or is it a matter of a failed test and not a failed function, if that is possible. As I understand it, the after burner treatment test is only performed occasionally as a monitoring function.  
Bottom line is I don't want to have to spend $2k to find out if the jets are bad or clogged. On the other hand, I don't want to be halfway to Newport, Or and have the engine light come on again. I would greatly appreciate any insight//advice which is always hightly valuable here. Thanks, in advance.

[Gerald Farris]

Ron,
If the check engine light does not come on you are not damaging the engine by driving the coach. However, the original reason that the check engine light came on is still there, so it will come back on eventually.

The ECM (engine control module) is programed to prevent you from damaging the engine if one of the operating parameters is too far out of specifications by derating (drastically reducing the power output) the engine or eventually causing it to shutdown.

The ECM monitors the condition of the DPF (diesel particulate filter) constantly with sensors that measure the pressure drop across the filter. When a restriction is detected, and the driving conditions are correct, the ECM will start the regeneration process to burn the excess carbon out of the filter. If the DPF is restricted, there will not be enough exhaust flow at an idle to register the restriction. So if you did not drive the coach under load after clearing the code, you do not know if the light is going to come back on or not.

Gerald

[Ron Langdon]

Thanks, Gerald. I really appreciate the response. Since I am not much of a gambler, and prefer surety, I will have Peterson's fix it tomorrow, although I would prefer being with Beaver friends at Pacific Shores on the Oregon Coast.
Thanks, again.