1998 S-10-E Electric Truck

===

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

===

DTC
Dianostic Trouble Codes

===


DTC-279

The S10E reported DTC-279 code upon acquisition c2008.  Upon
investigation we found resistance on the HV (high voltage) negative
battery box connection to the PIM when linked 
to chassis ground.  A 200 ohms scale was used for this test.

In the first phase we tested the circuit by “unplugging” all the
connectors from the overall PIM when it was still in the vehicle and
continued to get resistance readings from the HV negative
connector to chassis ground.  In the second phase we removed the
PIM from the vehicle, retested and received the same results.  We then
went to the third phase and, with the PIM out of the vehicle,
physically inspecting the interior of the PIM.  Then removed the
accessory modules from the PIM, retesting with each removal.  When
we removed the power steering control module (PSCM)
from the bottom of the PIM the resistance
reading to chassis cleared.

We subsequently opened the PSCM and retested, seperating the 
top half PSCM PCB from the bottom half and reconnecting to the PIM,
and the resistance reading reappeared.  The DTC-279 is now
located to the top half of the PSCM.

After disassembly of the PSCM and retesting the resistance reading
vanished.  We found  that mostlikely one of the two regulator
chips had a fault-to-ground at its insulated mounting screw.
The insulator was replaced and the PSCM has
been returned to service functioning properly.



===


--->  Additional pictures below  <---


===