TM 10-3930-675-20-1
0012 00-3
ELECTRONIC CONTROL UNIT (ECU) INPUT VOLTAGE TROUBLESHOOTING - CONTINUED
0012 00
Table 2. Error Code 122 - Supply Voltage to Servo ECU (790) Failure Troubleshooting Procedures.
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Error Code 122 - Supply Voltage to Servo ECU
(790) Failure
1. Remove cab circuit breaker
panel and ensure that circuit
breaker F32 is not tripped.
Reset circuit breaker as required
(WP 0073 00).
2. Check batteries for loose or
damaged cables.
Tighten or replace battery cables
(WP 0108 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 pin
7 and pin 8.
If voltage is present, replace
ECU (790) (WP 0079 00).
6. Check
for
voltage
at
connector X30 pin 2.
If voltage is present, notify SRA.
7. Check for voltage at circuit
breaker F32.
If voltage is present, notify SRA
to replace wire to (A302).
8. Check for voltage at relay 315
pin 87.
If voltage is present, notify SRA
to replace wire(s) (A808A,
A808B, and/or A808C).
9. Check
for
voltage
at
connector X80 pin 3.
If voltage is present, notify SRA
to replace wire (A804).
10.Check
for
voltage
at
automatic circuit breaker
F50-2.
If voltage is present, notify SRA
to replace wire (A803).
DIAG SERVO
1(13)
SYSTEM POWER
24.00V
POWER RI CAN
24.00V
POWER LE CAN
24.00V
10V REF OUT
10.00V
