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FW · 03-09-2012, 04:23 PM

Hi All; This code (434) is from using the onboard diagnostic switch.
According to the list I have, it means "unswitched battery supply circuit".
Does that mean a supply circuit that is directly from the battery, not the ignition switch?

Thanks in advance

FW

GaryKD · 03-09-2012, 04:55 PM

Hi FW,
Go to ~~~~~School Bus Mechanic: Cummins Engine Repair- ISC Engine Code 434 and read the narrative along side the pictures. It seems power to the ECM is provided directly from the batteries.

traderAl · 03-10-2012, 05:15 AM

Where is the "onboard diagnostic switch" I am unaware of that feature on my 2002 DSDP Cummins ISC? Would like to learn about that.

Al

FW · 03-10-2012, 10:13 AM

Traderal; On the left of my dash and down is a row of 6 switches (gen start, fog lights, air dump, etc.) with the diagnostic button the 6th from the left.
I push and hold, turn ignition to on(not starting), all lights will do there normal check and go out. If the warning and stop engine lights return and stay lit then there are no codes to read. If they start blinking, the warning lite will stay lit and the stop engine light will blink the code (four blinks a short pause three blinks a short pause four blinks a long pause repeat 434). There are some rigs that using the accelerator some way will do the same thing.

FW · 03-10-2012, 09:33 PM

GaryKD; After going to the link, I checked all the battery connections and while taking them off a connector with three wires going to it almost fell apart. The only way it stayed together was the electrical tape. It easily came apart when I removed the tape. I repaired it by making three single connectors instead of one large connector.
I won't know if I corrected the problem until I drive it again.
I'm waiting on a work assignment.
Thanks

traderAl · 03-11-2012, 07:55 AM

Thanks, FW. My coach doesn't seem to have that switch. I have heard that some MH's can retrieve the error codes by pushing the turn signal lever. Mine doesn't seem to have that either. I am still searching for a way to read out the error codes for my Cummins ISC on a Spartan chassis..

Hope you get your error code solved.

Al