TM 5-3805-293-23-1
0011
Table 2. Engine Troubleshooting with Codes for the 120M Motor Grader - Continued.
CDI FMI CODE
ERROR/EVENT
CORRECTIVE ACTION
1785-04 Intake Manifold
Test Step 1. Test Signal Circuit.
Pressure Sensor Voltage
N OT E
Below Normal - Continued
Always inspect the harness connectorsthat are involved in the circuit.
Poor connections can often be the cause of a problem in an electrical
circuit. Verify that all connections in the circuit are clean and secure,
and that all connections are in good condition. If a problem with a
connection is found, correct the problem and verify that this diagnostic
code is active before performing this procedure.
Perform open or short circuit test ateach harness connection to identify
correct harness to replace.
Perform this test only if condition is active.
1. Connect MSD (WP 0006). Select
Engine ECM C6.6 120M.
2. Start and run the engine and ver-
Diagnostic Code 1785-04 Active -
ify diagnostic code 1785-04 is
Proceed to step 3.
active.
3. Turn ignition switch to the OFF
position.
4. Disconnect the intake manifold
pressure sensor harness connec-
tor EA-C7 (WP 0009, Figure 24)
from intake manifold pressure
sensor.
5. Start and run the engine.
N OT E
Wait at least 30 seconds in order for diagnostic codes to become active.
1785-04 Remains Active - Proceed
6. Using MSD (WP 0006), select
to step 7.
Engine ECM C6.6 120M, and
check if diagnostic code 1785-03
1785-03 Becomes Active - Sensor is
is active.
faulty, replace intake manifold
pressure sensor (WP 0107).
7. Using a digital multimeter, check
Voltage OK (4.84 - 5.16 Volts) -
5-Volt supply circuit for voltage
5-Volt supply circuit T997-OR and
between intake manifold pres-
Engine ECM test OK, proceed to step
sure sensor harness connector
8.
EA-C7 (WP 0009, Figure 24) ter-
Voltage NOT OK - Proceed to Test
minal 1 and ground.
Step 2.
Voltage should be within 4.84 - 5.16
Volts.
8. Turn the ignition switch and bat-
tery disconnect switch to the OFF
position.
Change 1
0011-162
