Table 2. Engine Troubleshooting with Codes for the 120M Motor Grader - Continued.
CDI FMI CODE
Temperature Sensor Voltage
ECM will use default value of
158°F (70°C) for intake manifold
Cooling fan will operate at maxi-
A warning will appear on messen-
ger. ECM will log diagnostic code.
Possible Performance Effect:
Poor cold running
N OT E
The Engine Electronic Control Module (ECM) continuously outputs a
pull-up voltage on sensor signal circuit. The Engine ECM uses this pull-
up voltage to detect an open in the signal circuit. When the Engine ECM
detects the presence of voltage that is above a threshold on signal
circuit, the Engine ECM will generate a voltage above normal diagnostic
code for the sensor.
The signal circuit is a regulated 5-Volt supply within the Engine ECM.
The supply voltage is 5.0 ± 0.05 Volts. The signal circuit from the
Engine ECM J2-42 circuit 967-BU to the intake manifold temperature
sensor harness connector EA-C8 terminal 1. The return circuit is a
common ground from the Engine ECM J2-37 circuit L731-BR and is
spliced externally of the ECM to the intake manifold temperature sensor
harness connector EA-C8 terminal 2, and the engine coolant
temperature sensor harness connector EA-C9 terminal 2.
Test Step 1. Test Signal Circuit.
N OT E
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.
Engine ECM C6.6 120M and
verify 0172-04 is active.
2. Turn ignition switch to the OFF