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
5. On MSD, select C6.6 924 and
1785-4 Intake Manifold
Diagnostic Code 1785-4 Intake
check for active diagnostic codes
Pressure Sensor Signal
Manifold Pressure Sensor Signal
Voltage Is Below Normal or
Voltage Is Below Normal Remains
Active - Proceed to Test Step 3.
the Voltage Is Shorted Low -
Continued
Diagnostic Code 1785-4 Intake
Manifold Pressure Sensor Signal
Voltage Is Below Normal Becomes
Inactive - Replace air (boost) pressure
sensor (WP 0242).
Proceed to Test Step 4.
Test Step 3. Test for Shorted Engine
Control Wiring Harness.
1. Turn ignition switch and battery
disconnect switch to OFF position
(TM 5-3805-298-10).
2. Disconnect connector E-C4
(WP 0012, Figure 10) from engine
ECM connector J2.
3. Using digital multimeter
Continuity - Replace engine control
(WP 0174), test for continuity
wiring harness (WP 0294).
between connector E-C4
Proceed to Test Step 4.
(WP 0012, Figure 10) terminal 55
No Continuity - Proceed to step 4.
and terminal 38.
4. Using digital multimeter
Continuity - Replace engine control
(WP 0174), test for continuity
wiring harness (WP 0294).
between connector E-C4
Proceed to Test Step 4.
(WP 0012, Figure 10) terminal 55
No Continuity - Replace engine ECM
and ground.
(WP 0265).
Proceed to Test Step 4.
Test Step 4. Verify Malfunction Is
Resolved.
1. Ensure all wiring harness
connectors are connected.
2. Install right engine access panel
(WP 0348).
3. Connect MSD. Select C6.6 924
Diagnostic Code 1785-4 Intake
and check for active diagnostic
Manifold Pressure Sensor Signal
codes (WP 0008).
Voltage Is Below Normal Becomes
Inactive - Troubleshooting complete.
Diagnostic Code 1785-4 Intake
Manifold Pressure Sensor Signal
Voltage Is Below Normal Remains
Active - Repeat troubleshooting from
the beginning.
0064-5
