TM 5-3805-290-23-1
ELECTRICAL SYSTEM TESTS, INSPECTIONS, AND ADJUSTMENTS - CONTINUED
0013 00
5V ENGINE PRESSURE SENSOR SUPPLY CIRCUIT TEST - CONTINUED
N OT E
The bypass harness directly connects the engine start switch circuit to the ECM. The ECM will have power
until the connection to the + battery cable is disconnected. Remove the F1 fuse from the inline fuse holder in
order to switch off the ECM.
e.
Remove fuse from bypass harness and battery circuit.
f.
Connect unswitched battery cables directly to battery terminals.
g.
Install fuse on bypass harness inline fuse holder.
h.
Turn engine start switch to ON position (TM 5-3805-290-10).
N OT E
When ECM engine harness connector J1/P1 is disconnected and the engine start switch is in the ON posi-
tion, open circuit diagnostic codes will be "Active" or "Logged" for all of the engine sensors. This is normal.
i.
Access active diagnostic code screen on ET. Check for one of these active diagnostic codes:
(1)
262-03 5V Sensor dc Power Supply Short to +Batt.
(2)
262-04 5V Sensor dc Power Supply Short to Ground.
j.
If +5V diagnostic code is active when bypass harness is connected, replace engine ECM (WP 0053 00). Verify
repair eliminates problem.
k.
If +5V sensor diagnostic code is no longer active when bypass harness is connected, either harness or a sensor
attached to harness is causing problem. Reconnect ECM engine harness connector (WP 0053 00). Proceed to step
4.
4.
Disconnect +5V sensors while active diagnostic codes are being monitored.
a.
Connect MSD (WP 0006 00).
b.
Turn engine start switch to ON position (TM 5-3805-290-10).
c.
Access active diagnostic code screen on MSD. Verify one of these diagnostic codes is active:
(1)
262-03 5V Sensor dc Power Supply Short to +Batt.
(2)
262-04 5V Sensor dc Power Supply Short to Ground.
d.
Disconnect these sensors one at a time:
(1)
Engine oil pressure sensor (WP 0066 00).
(2)
Boost pressure sensor (WP 0065 00).
e.
Wait for 30 seconds after each pressure sensor is disconnected while MSD is being monitored to verify that discon-
nection of specific sensor deactivates +5V diagnostic code.
0013 00-8