TM 5-3805-298-23-1
0064
Table 1. 1785 Intake Manifold Pressure Diagnostic Codes - Continued.
064
CID FMI CODE
TEST OR INSPECTION
CORRECTIVE ACTION
NOTE
1785-4 Intake Manifold
Pressure Sensor Signal
Always inspect wiring harness connectors that are involved in the circuit.
Voltage Is Below Normal or
Poor connections can often be the cause of a problem in an electrical
the Voltage Is Shorted Low
circuit. Verify that all connections in the circuit are clean and secure and
that all connections are in good condition. If a problem with the
connection is found, correct the problem and verify that this malfunction
or diagnostic code is active before performing this procedure.
Perform open or short-circuit test at each wiring harness connection to
identify the correct wiring harness to replace.
Tag all wiring harnesses to aid in installation.
Perform this test only if condition is active.
DIAGNOSTIC CODE SET CONDITION
Engine ECM detects signal voltage from the intake manifold pressure sensor is
less than 0.1 Volts DC for more than eight seconds.
POSSIBLE CAUSE
Engine control wiring harness is shorted to ground.
Intake manifold pressure sensor is shorted.
Engine ECM.
Test Step 1. Check for Active
Diagnostic Codes.
Connect MSD. Select C6.6 924 and
Diagnostic Code 1785-4 Active -
Proceed to Test Step 2.
check for active diagnostic codes
Diagnostic Code 1785-4 Not Active -
Troubleshooting is complete.
Test Step 2. Test for Shorted Intake
Manifold Pressure Sensor.
1. Turn ignition switch and battery
disconnect switch to OFF position
(TM 5-3805-298-10).
2. Remove right engine access panel
(WP 0348).
3. Disconnect connector E-C8
(WP 0012, Figure 30) from intake
manifold pressure sensor.
4. Turn battery disconnect switch ON
and start engine (TM 5-3805-298-
10).
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