My recently purchased '07 MCS had it's check engine light (CEL) come on a few days ago. I took it to the dealership immediately and it was diagnosed with 2 repeating fault codes. Service advisor said first code relates to the intake manifold and he assumes it's because of the previously repaired (tape job) cracked turbo inlet tube. The other code relates to the post-cat O2 sensor. Basically, the recommendation was to replace both (along with a leaking valve cover) for nearly $1500. I decided limp with the car for a while and have my inde shop do the repairs next week.

I picked up the car from dealership after diagnosis last Saturday with the CEL off. I assumed they cleared the faults. Drove about 2 hours, then CEL came back on. Didn't drive it Sunday nor Monday due to CEL concerns. Drove today for about 25 miles with CEL remaining on. Just a while ago, after a short run to the market, the CEL automatically remained off after starting up the car. Does anyone have ANY idea what could be going on here?

Also, it seems like the engine fan always turns on after I shut off the car. Whether it be after 45 minute drive or a 5 minute quick run. Is this normal?! The fan stays on for about 5+ minutes each time.

Can anyone provide insights

Thanks in advance.

 

a shot in the dark; everytime I had weird things going on. like a code thrown for a cooling sensor , and weird things happening , I changed the battery and everything went away. If your battery is old, you might try that first. Give it several start ups to clear itself. The car will start but the electronics don't like the low voltage, I'm guessing.

 

get yourself a cheap code reader other wise it's just too much guessing.

 

Ask them exactly what codes they detected (should be part of the paperwork mechanics returned to the SA. Either that, or buy your own code-reader (or take the cat to AutoZone for free code scan) so that we can zoom in on the problem.

I will assume that the turbo inlet tube's tape repair is not holding all that well, so replace it as injecting unmetered air into the engine can lean to uncontrolled lean mixture and engine damage down the road! Either with an OEM, or an aftermarket pipe, but replace it ASAP.

A rich/lean running engine (see above) can also damage the cat over time, and trip 02 sensors!

The fan will run to cool the turbo if it gets too hot. So will the auxiliary water pump, circulating the coolant through turbo for additional cooling.

Both conditions can be mitigated if you lay off hard acceleration for a few minutes before you park, and coast home. The aux coolant pump may still run, but the engine fan will either turn off sooner, or never come on at all.

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