
72 RENR9348-01
Troubleshooting Section
i02407894
CID 1785 FMI 04 Intake
Manifold Pressure Sensor
voltage low
SMCS Code: 1439-038-IL
Conditions Which G enerate This Code:
The Electroni
c Control Module (ECM) detects a
signal voltage below the normal.
System Respon
se:
The code is logged. The ECM flags intake manifold
pressure as in
valid data and a default value is used.
Possible Performance Effect:
•
The engine power will be derated.
Troubleshoo
ting:
Perform the following diagnostic procedure: “Engine
Pressure Sen
sor Open or Short Circuit - Test”
Results:
•
OK – STOP.
i02487751
CID 1785 FMI 10 Intake
Manifold Pressure Signal
abnormal ra
te of change
SMCS Code: 1439-038-IL
Conditions Which G enerate This Code:
This code in
dicates that the 5 volt supply is missing
from the sensor connector.
During norm
al engine operation, the intake manifold
pressure fluctuates slightly. When the 5 volt supply is
missing from the intake manifold pressure sensor, the
signal fro
m the pressure sensor floats to a midrange
value. The signal does not fluctuate. If the signal
from the intake manifold pressure sensor remains
abnormall
y steady for more than 30 seconds, the
Engine Control Module (ECM) activates this code.
System Res
ponse:
The ECM uses a default value for the intake manifold
pressure.
Possible Performance Effect:
•
Low power
Tr oubleshooti
ng:
Repair the Sensor S upply Circuit
A. Repair the circuit for the supply wire between the
ECM and the sensor.
Expected Result:
The problem is
resolved.
Results:
•
OK – The problem is resolved. STOP.
•
Not OK – The pro
blem is not resolved.
Repair: Replace the sensor.
STOP.