Rewiring the Instrument Panel on Certain C175-16 and C280-16 Petroleum Engines{7451} Caterpillar

Engine:

C175-16 (S/N: P6L1-UP)

C280-16 (S/N: NKB1-UP)

Introduction

Panels that were built before 19March 2013 were configured to shut the Diesel Control Unit (DCU) off whenever the control panel key switch was turned off. In this configuration, the DCU can take up to 60 seconds to boot up and be ready for engine operation. The panels that were built after 19March 2013 are configured with a "System Off" function. In this mode, the DCU internal circuitry is active, but the screen of the DCU powers off. The DCU will remain powered until the main 24 VDC battery connection is removed. Follow these instructions to reconfigure the panel to have "System Off" functionality. Reference Schematic, UENR5135, "GMS 3.0 Panel Electrical System".

Rework Procedure

Illustration 1	g03642886
Caterpillar Alarm & Protection System with DCU.

Illustration 2	g03642899
Location of the SPMR and the PPMR inside the DCU panel. (1) SPMR (2) PPMR

Illustration 3	g03643198
The connections on the back of the DCU. (3) Pin 1 (4) Pin 3 (5) Pin 7 (6) Pin 8

Illustration 4	g03643199

1. Remove wire A114-A182 YL-18 from the DCU "PIN 1" (3 ) .

2. Cut the connector from the end of A114-A182 YL-18. Loop the end of the wire and apply heat shrink tubing over the loop. Secure the wire to the existing harness.

3. Remove wire 145-A187 BU-18 from the DCU "PIN 3" (4) .

4. Cut the connector from the end of 145-A187 BU-18. Loop the end of the wire and apply heat shrink tubing over the loop. Secure the wire to the existing harness.

5. Remove wire 170-A231 YL-18 from the DCU "PIN 7" (5) and "PIN 8" (6) .

6. Remove wire A114-A186 YL-18 from the PPMR (2) connection 14.

7. Cut the connector from the end of A114-A186 YL-18. Loop the end of the wire and apply heat shrink tubing over the loop. Secure the wire to the existing harness.

8. Remove wire 161-A105 RD-18 from the SPMR (1) connection 11. Reroute the wire to connect to "PIN 3" (4) on the back of the DCU (additional wire length will be required).

9. Remove wire 115-A120 RD-18 from the PPMR (1) connection 11. Reroute the wire to connect to "PIN 1" (3) on the back of the DCU (additional wire length will be required).

10. Remove the "SMPR" label. The relay will no longer be used.

11. Change the "PPMR" label to a "PMR" label.

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Illustration 5	g03643216

12. Route a new yellow 18 gage wire (170-A231 YL-18) from the PMR connection 11 to the DCU "PIN 7" (5) .

13. Route a new black 18 gage wire (A170-A165 BK-18) from the PMR connection 14 to the DCU "PIN 8" (6) .