2005/06/06 Caterpillar

Generator Set:

G3520C (S/N: MAD1-UP; HAT1-UP; CWW1-UP; CWY1-UP; GDB1-UP; GHC1-UP)

G3520E (S/N: SXY1-UP; GHM1-UP)

Two new options are available for replacing the 149-5150 Pressure Sensor Gp on G3500 Engines. The first replacement option uses the 161-1704 Pressure Sensor Gp. Installation of this sensor requires fabrication of a harness.

The second replacement option uses the 194-6724 Pressure Sensor Gp. Installation of this sensor requires the use of a 261-5678 Engine Harness As .

Table 1 lists the flash files that are required in order to use either the 161-1704 Pressure Sensor Gp or the 194-6724 Pressure Sensor Gp.

Illustration 1	g01173031
Enclosure for the ECM (1) J7 connector

Illustration 2	g01172838
Existing 149-5150 Pressure Sensor Gp schematic

Illustration 3	g01172949
New 161-1704 Pressure Sensor Gp and 194-6724 Pressure Sensor Gp schematic

Procedure for Wiring the New Pressure Sensor Groups

For Steps 1 and 2, refer to Illustration 2.

1. Remove the following wires from the J7 connector inside the enclosure for the electronic control module (ECM): J7-43, J7-15 and J7-29.

2. Insulate each pin of the removed wires (43, 15, 29) with heat shrink tubing or with electrical tape. Tie the wires to the harness bundle. These wires will not be used.

   For Steps 3 through 5, refer to Illustration 3.

3. Remove wire J7-45 from the J7 connector inside the enclosure for the ECM. Remove the pin from the end of the wire and splice two 16 AWG wires onto this wire. The wires should be approximately 300 mm (11.8 inch) long. Terminate the two wires with 8T-8729 Connector Pins. Insert the wires into the J7 connector. Insert one wire in the J7-45 position. Insert the second wire in the J7-43 position. This will provide +5 VDC to the pressure transducer.

4. Remove wire J7-20 from the J7 connector inside the enclosure for the ECM. Remove the pin from the end of the wire and splice three 16 AWG wires onto this wire. The wires should be approximately 300 mm (11.8 inch) long. Terminate the three wires with 8T-8729 Connector Pins. Insert the wires into the J-7 connector. Insert one wire in the J7-20 position. Insert the second wire in the J7-15 position. Insert the third wire in the J7-29 position. These wires provide the sensor common and the shield.

5. At the ECM, remove wire P1-10 from the P1 connector. Insert the wire into the P1-15 position. This wire provides the signal input to the ECM.

   To install the 161-1704 Pressure Sensor Gp, perform Steps 6 and 7.

   To install the 194-6724 Pressure Sensor Gp, perform Steps 8 and 9.

6. Install the 161-1704 Pressure Sensor Gp in place of the original sensor. The existing adapter fitting must be used with the new pressure sensor. The adapter fitting serves as a mounting base for the sensor.

7. Fabricate a 300 mm (11.8 inch) adapter harness that uses the following components: one 155-2276 Plug Lock Wedge, one 155-2267 Connector Plug As, one 8T-8731 Connector Plug and six 8T-8730 Connector Sockets. The following connections must be made at the inlet manifold pressure sensor: A to A (+5 VDC), B to B (common) and C to C (signal).

8. Install the 194-6724 Pressure Sensor Gp in place of the original sensor. The existing adapter fitting must be used with the new pressure sensor. The adapter fitting serves as a mounting base for the sensor.

9. Install the 261-5678 Engine Harness As. This harness assembly provides the interface between the new sensor and the existing engine harness.