Our new to us (September 2011) 2003 S has thrown a P1688 code twice. We are the second owner and the car has about 26K miles currently.

Both events occurred under hard acceleration at approximately 5.5K RPMs. The car goes into limp mode but resets after a key cycle and seems to be fine afterward.

The car does not seem to develop much power until higher speeds/RPM's are achieved and is rather sluggish, especially off idle.

Would the consensus of opinion be to replace the Bypass Valve? Also, any positives on the Detroit Tuned modified valve?

 

Was able to capture the following freeze frame data on the ScanGauge2:

PID02 = 1688
PID03 = 0400 / Loop is Open
PID04 = 3F / LOD = 24
PID05 = 85 / WT °f = 198
PID06 = 80
PID07 = 89
PID0B = 6C / MAP PSI = 15.8
PID0C = 22FA / RPM = 4477
PID0D = 73 / MPH = 71

Looks like I was 1K high on the previously stated RPM.

 

I was able to duplicate the above errors this afternoon on the freeway. Same scenario, same captured data.

The plan at this point from some expert advice received:

- Zip Tie BPV and test for recurrence/resolution of event

- Replace crank pulley / damper with ATI Super Damper, as preventive maintenance in light of vehicle year '03, and test for recurrence/resolution of event

We also intend to add a tensioner stop, new belt, and (as long as we're in there) a 15% SC pulley.

Comments?

 

Did you ever resolve this? I'm having the same problem in my '06.

 

Double post!

 

same thing here, seems to be a blown damper crank pulley, as i started smelling some burned rubber. BPV has been checked and works fine.
I need advice in changing this crank pulley. I've seen at WMW the ATI super damper, the liquid crank damper and the M7 2% crank pulley. the thing is can i replace my burned out crank pulley with any of theese? or those "lightened" crank pulleys are "attached" to the dumper cp?
would you recommend going for a 0% lighthened pulled along with a 15% sc pulley change?
on the other hand, i'll be changing the clutch, i've read here that the SPec is no good, and that the Valeo should be fine. any fresh info on this?

thanks in advance, as i'm from abroad and in need to drive my MCS, but without replacement parts, i'm having at least 10 days of driving the wifes suv.....

 

Yes, the code has been resolved. Unfortunately, we threw a few variables into the mix and do not have a feel for the true resolution.

Here's what we did:

1. Replaced VERY dirty air filter (thought dealer had done this, nope!)
2. Changed Oil and Filter (thought dealer had done this too, nope!)
3. Replaced the crank damper with an ATI (preventive on our '03)
4. Installed a 15% SC pulley and Gates "39" drive belt
5. Installed MSD Coil, Wires, and Denso (5310) IK22 Iridium Plugs (1 step colder for 15% pulley)
6. Full Reset of Computer

We also did a "zip-tie" test on the BPV and it made no difference. I'd start with an inspection of your air filter and go from there. Best of luck in your quest!

 

According to the MINI Cooper Diagnosis Without Guesswork book:

P-code: P1688
MINI FC(fault code): 5768
Description: Monitoring of mass air flow
Threshold Value: Low MAF limit exceeded n threshold map
Related components: Electronic throttle actuator, Supercharger operation

Not sure what this all means, but hope this helps....

 

Just got home from my mechanic facility, and yes, my crank pulley is dead.
I will chnage it with the craven speed lightweight crank pulley, belt and sc 15% pulley. Aside from that, do you think i should change the belt tensioner, tension roller and other moving parts?
After that is sorted right, we wil have to check the bpv and other stuff in order to get rid of the p1688 code......

Any suggestions, advise, best places to get parts, etc will be wellcome

 

Faer:

On your question of replacing the belt tensioner, you did not mention the year or car mileage.

On my 2004 MCS with 75k miles, I have a M7 2% crank pulley with a 15% supercharger pulley. Mine is a daily driver... So far, I detect no noise or issues from the belt tensioner, but I plan to change a bunch of stuff ((fuel,air,cabin filters), plugs, wires, tranny oil, etc) at 100k, including the tensioner if it is not replaced beforehand....

Be aware that if you do a reduction on the supercharger pulley or crank pulley, I recommend changes at regular intervals. I currently do mine at about 20k miles....

Hope this helps...

 

Thanks spirit,
Sorry, mine is a 2005, 47.000 miles, mec trans., a/c, currently without any mod.
i haven't got the knowledge so as to check the right noise....so...i think i'll get a new one
Any advise on clutches?, thinking about the valeo kit, but for the std dual mass flywheel
I'm from Chile and my car is about to complete two weeks on the mechanic, and hopefully i'll be placing my orders tomorrow, so i'll get the parts by mid february....

 

I decided against the lightweight crank pulleys and went with the ATI Super Damper. Summit Racing had a great deal on them. The crank damper is just that, it dampens vibrations from the crank shaft. I don't think there is enough data on the lightweight pulleys that demonstrate bearing life over the long haul. Since I don't plan to tear into the bottom end of this engine, I wanted to get as much out of it as I can long term.

Remember that with any SC reduction or damper overdrive, you'll need a shorter drive belt and colder spark plugs to help manage the additional heat that is produced by the increased boost pressure. You might also want to consider the addition of a tensioner stop as they are rather cheap insurance in the even of a belt failure.