Carrier VECTOR 6500 Operation & Service Manual page 209

Alarm
Steps
NO.
P145 CHECK SPEED SOL CIRCUIT
•
TRIGGER–ON: Normal Amps for the Speed Solenoid Circuit is 0 to 1.0 Amps. The circuit tests out-
sidethis range.
•
UNIT CONTROL: Alarm Only
•
RESET CONDITION: Auto Reset if Pretrip is started again or alarm may be manually reset via
keypad or by turning the unit off then back on again.
1 Check For Bad F2 Or F3 Fuse Alarm
Check for Alarm 71.
2 Check Speed Circuit To ENSCU And FSA
a. Check voltage to ENSCU and amp
draw of engine speed control circuit
(ENSCU) pin 16 and MPQC3 on the
microprocessor.
b. Check operation of Speed Relay
LED
3 Check Engine Speed Control Unit (ENSCU)
a.Check resistance of FSA
b. Inspect ENSCU and wiring
4 Check ENSCU Circuit Wiring
Inspect harness & control box con-
nector pins & terminals (See wiring
schematic)
62-11389
Alarm/Cause
7−76
Corrective Action
Alarm conditions must be corrected and the alarm
cleared to continue.
Use Component Test mode to energize the Speed
Relay. (Section 5.2.2)
Refer to Section 2.12 for amp values.
View current draw in the Unit Data. (Refer to Section
3.13).
Check voltage at ENSCU16 and ground. Must be 11
VDC or higher.
LED 27 must be ON when the Speed Relay is ON in
component Test Mode.
Refer to Section 2.12. With FSA unplugged, ohm
spec is 3 to 4 ohms, $ 10%.
No physical damage to harness.
No damage, moisture, or corrosion in connectors.
No damage to ENSCU
No physical damage to harness.
No damage, moisture, or corrosion in connectors.