TM 10-3930-675-24-1
BRAKE SYSTEM TROUBLESHOOTING - CONTINUED
0031 00
Table 3. Error Code 120 - Brake System Pressure, Circuit 2 Failure Troubleshooting Procedures.
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Error Code 120 - Brake System Pressure, Circuit 1. Check if accumulator evac- Close accumulator evacuation
uation valves are open (WP valves.
2 Failure.
0164 00).
2. Check brake system pressures If pressure is not as specified,
at test points 1 and 2 (WP 0187 perform brake system
troubleshooting (WP 0005 00).
00).
A "0" at either brake circuit
3. Enter "EXTRA FUNC" 7(13)
would indicate an open pressure
in the diagnostic menu and
switch due to low brake pressure,
check status of both brake
EXTRA FUNCT.
7(13)
faulty pressure switch or open
circuits.
circuit.
BRAKE CIRCUIT 1
0
BRAKE CIRCUIT 2
0
4. Check circuit breaker F3 for Reset circuit breaker as required.
trip.
5. Start engine and allow brake a. If no voltage (24V) is found,
pressure to built up. Check
proceed with step 6.
voltage (24V) at X150 pin 10 b. If voltage (24V) is present,
(WP 0048 00-7).
disconnect
ECU
(790)
connector 1 and inspect pin 41
for damage (WP 0048 00-7).
6. Check voltage (24V) at X18 a. If no voltage (24V) is found,
pin 1 (WP 0048 00-36).
check circuit breaker F3 and
continuity of wires A266 and
A181.
b. Repair or replace damaged
wires or connectors (WP 0113
00).
c. Replace damaged or faulty
circuit breaker (WP 0074 00).
7. Check voltage (24V) at X18 a. If no voltage (24V) is found,
pin 3 (WP 0048 00-36).
remove panel in front of the
brake pedals and check
connections at the brake
pressure switches 204-1 and
204-2 (WP 0098 00).
b. With the brake pressure built
up, check continuity of
pressure switch 204-2 (WP
0113 00).
c. Replace faulty pressure switch
(WP 0098 00).
8. Check continuity of wires 181, Repair or replace damaged wires
A181, 183, A183, 296, and or connectors (WP 0113 00).
A15010 (WP 0048 00-7 and
WP 0048 00-36).
0031 00-4
