STEP/SEQUENCE
RESULT
WHAT TO DO NEXT
TM 9-2320-363-20-1
Section 4
TROUBLESHOOTING CHARTS
E. VEH5V · VEHICLE HARNESS +5 VOLTS SUPPLY (CONT'D)
VEH5V.4
Check for +5 Volt
Short Ground
Remove jumper wire
Both readings are
Go to VEH5V-10.
Disconnect PTOSA and/or Fast
greater than 10,000
idle resistor network if installed.
ohms or open.
Read resistance between pins A
and C of the TPS harness
Either reading is
Go to VEH5V-5.
connector.
less than or equal
Also read resistance between pin
to 10,000 ohms.
C or the TPS harness connector
and a good ground.
VEH5V.5
Check if There is a
PTOSA Sensor
Does the engine have a Power
No.
The engine +5 volt line (ckt#916)
Take-Off Speed Adjust (PTOSA)
is shorted to either the sensor
Sensor?
return line (ckt #952) or to chassis
ground (if there is a Fast Idle
switch, the short may be at the
resistor network used). Repair
short. Then go to VEH5V-30.
Yes.
Go to VEH5V-6.
VEH5V.6
+5 Volts Check
Using the PTOSA
Turn ignition off.
Less than
The engine +5 volt line (ckt #916)
Disconnect the Power Take-Off
4.7 volts.
is shorted to either the sensor
Speed Adjust (PTOSA) Sensor
return line (ckt #952) or to
and/or Fast Idle resistor network.
chassis ground. Repair short.
Turn ignition on.
Then go to VEH5V-30,
Read voltage on the PTOSA
harness connector, socket C (red
Greater than
Go to VEH5V-12.
lead) to socket A (black lead).
or equal to 4.7 volts.
Change 3 3-345.421
