1998 S-10-E Electric Truck
EV1 System 110 Inverter

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1998 S-10-E Electric Truck
EV1 System 110 Inverter

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DTC
Dianostic Trouble Codes


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DTC-104

DTC-104 is described as auxiliary battery low voltage.

We recently noticed that the S10E's 12v auxiliary systems were not
being supported by the APCM and investigated.  When the auxiliary
battery is resting at key-off the system should show a nominal
12.x v level; vs, key-on the 12v systems should increase
to +/- the 14.2v level.  The DTC-104 diagnostic instructions lead us
to item 11, and the stock GM answer of "replace APCM".  Well,
that would not be any fun, so we ventured into dianosing
what had failed in the APCM.

The pictures below show the results, a burnt transformer leg which,
when diagnosed, led back to a failed rectifier, a Schottky Rectifier
PN  203CMQ100.

After various testing as noted below the rectifier was determined
to be the root cause of the failure and subsequent burnt transformer
leg.  The transformer tested nominal so the leg was
repaired and the transformer placed back in service.  The 
rectifier was then replaced with NOS stock and the
APCM put back in service.

DTC-104 then successfully cleared and the APCM 
operates nominally.



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--->  Additional pictures below  <---


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