TM 10-3930-675-20-1
0012 00-1
ELECTRONIC CONTROL UNIT (ECU) INPUT VOLTAGE TROUBLESHOOTING
0012 00
THIS WORK PACKAGE COVERS
Error Code 121 - Supply Voltage to Servo ECU (790)
Failure
Error Code 122 - Supply Voltage to Servo ECU (790)
Failure
Error Code 123 - 10V Reference Voltage for Servo ECU
(790) Failure
Error Code 201 - Supply Voltage to Tophandler ECU
(791) Failure
Error Code 202 - Supply Voltage to Tophandler ECU
(791) Failure
Error Code 203 - 10V Reference Voltage for Tophandler
ECU (791) Failure
INITIAL SETUP
References
TM 10-3930-675-10
Current Supply (A34738.0200) (WP 0199 00-31)
References - Continued
ECS Attachment (A34652.0200) (WP 0199 00-23)
ECS Electrical Servo (A34648.0200) (WP 0199 00-5)
NOTE
•
Refer to WP 0004 00 for additional troubleshooting guidance, information, and illustrations
that locate critical components.
•
Refer also to illustrations at end of work package for component location.
Table 1. Error Code 121 - Supply Voltage to Servo ECU (790) Failure Troubleshooting Procedures.
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Error Code 121 - Supply Voltage to Servo ECU
(790) Failure
1. Ensure that emergency stop
switch is not activated.
Release emergency stop switch
as required (TM 10-3930-675-
10).
2. Remove cab circuit breaker
panel and ensure that circuit
breakers F30 is not tripped.
Reset circuit breaker as required
(WP 0073 00).
3. Check relay (315) for proper
function.
Replace relay if shorted (WP
0073 00).
4. Check
automatic
circuit
breaker F50-2 for proper
function.
Replace
circuit
breaker
if
shorted (WP 0073 00).
5. Disconnect
ECU
(790)
connector 1 from ECU and
perform voltage check at
connector pins 1 and pin 15.
If voltage is present, replace
ECU (790) (WP 0079 00).
