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'98 SLK 230
12 Posts
Discussion Starter · #1 ·
...and activates CEL with a list of codes.

When this first happened, I took the car to a Indy shop that diagnosed a power problem and replaced battery and alternator. Car ran great — for a day, then problem returned (CEL, blown fuse, very sluggish acceleration.)

A third recommended shop had the car for two days trying to trace the short, and this is what they’ve found:

“Short on K40, connector E, terminal 5, black wire with white tracer.
Possible ME2 output stage short.”

Fuse still blows when disconnecting all components on that circuit (that trip a fault), but he could not find a wiring diagram that shows exactly where that terminal 5 wire leads.

He suspectEd that this P0446-37 code (“Y58/4 Activated charcoal canister shut-off valve, The output stage of control module ME-2 SFI is faulty”) indicates that there is a problem in the ECU, and he recommends sending it out for test/repair.

Car still runs, no supercharger, of course, with other codes P1420, P0443, P1525, P0805, P0806.

I disconnected the battery (both terminals) for a while, replaced the fuse, and the car ran fine for two months, then the problems returned. Now, if I do the battery disconnect reset and replace the fuse, the car will start without showing CEL, but no supercharger. The next time car is started, CEL shows, and that K40 fuse #2 is burnt before starting the second time. (Fuse still blows with supercharger clutch unplugged.)

I have since found a diagram that shows that terminal 5 wire feeds through Z7/6:
  • purge control valve, Y58/1
  • charcoal filter cut-off valve Y58/4
  • O2 sensor 1 (Upstream)
  • O2 sensor 2 (Downstream
K40 and upstream O2 sensor have been replaced, problem persists.

A recent trip to Autozone revealed these codes:
P1420 air pump switch over valve
P0446 evap emission system vent control circuit
P0443 evap emission system purge control valve circuit
P1525 RH adjustable camshaft timing solenoid
P0805 clutch position sensor circuit
P0806 clutch position sensor circuit range/performance
P0135 O2 heater circuit (bank 1, sensor1)

Suggestions, please?
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