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K-40 FUSE HELP PLEASE

10K views 9 replies 5 participants last post by  Edwardfla 
#1 ·
Would someone please identify this fuse and it's purpose please? The fuse is blowing after about 20 minutes of driving.

Help and advice is greatly appreciated!
 

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#2 ·
Ok, just checked internals of K40, nothing unusual. I had previously soldered a bad joint, still looked good. I put K40 back in the car and placed a 20A fuse in the F2 slot. Hooked battery up, started car and BAS /ASR light stayed on, no SC engagement. I did the same yesterday and fuse didn't blow until later. Today it was immediate with the 20A fuse..... I have searched and searched the threads for more info on the F2 fuse. I found something yesterday but not today...UGH. I really need some help here PLEASE!
 
#4 ·
It looks like there is a short?

Have you scanned your car for ODB2 error codes?

I looked up F2 fuse in WIS workshop, its a fuse for "circuit 87" in the engine mangagment computer (ME). this circuit looks after

- fuel injectors
- air pump switch over valve
- o2 sensor 1 upstream

check your car with a reader for codes, im sure its thrown some and you will narrow down exactly whats going on.... post back here :thumbsup:
 
#5 · (Edited)
Thanks Subby, it is showing the following codes:

P0443
P0446
P1235
P1236
P1420
P1525

I checked the Vent/Purge valve solenoid, it has zero resistance, wonder if it is causing the short? P0443 and P0446 point towards it. Figure I might start there, unless you suggest something different. What and where is the pump switchover valve, same thing? I will wait to hear from you or others.

Thanks again sir.
 
#6 ·
a few codes there but they all look like they point to emissions system!

Auxiliary Emissions Controls Codes
P0443 - Evaporative Emission Control System Purge Control Valve Circuit
P0446 - Evaporative Emission Control System Vent Control Circuit

MB Specific Codes - Fuel & Air Metering
P1235 - Air-flap recirculated signal output stage faulty
P1236 - A/C compressor output stage, magentic combination incorrect

MB Specific Codes - Auxiliary Emission Controls
P1420 - Air-pump switchover valve circuit

MB Specific Codes - Vehical Speed, Idle Control, and Auxiliary Inputs
P1525 - Right or sole adjustable camshaft timing solenoid electricly faulty


attached is the diagram of the r170 system (m111 motor 4cyl). the air-pump is on cars with stricter emissions and its near the supercharger.

air pump = Y32 on diagram
purge valve = Y58/1 on diagram
vent valve = 76 on diagram

also check the cam advance magnet under as they tend to leak oil when they go bust and can wick up oil up the loom :eek: (can find threads on this)...

as for checking diagnostics ill sus out WIS a bit deeper later... reset the codes and run the car for a few days and see which ones re-apear the more serious ones will re-appear almost immediatly. some of the above could have been once offs...
 

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#8 ·
If you could swap one over to see if any codes come back? i measured my purge solenoid before and it read 50 Ohms. im not sure how much voltage they run on (could measure the voltage on the electrical connector) and take the valve out and apply voltage to it to see if it clicks or makes any noise?
 
#9 ·
Your year car is known to have bad K40's The fuse blowing on the K40 might just point to a bad K40.. A K40 is fairly cheap most around a $100.

Not trying to stop your search but see if some one local is willing to swap for a few hours to eliminate this as a problem..
 
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