Generator Set Control Panel for Switchgear Conversion Caterpillar

Illustration 1	g00564972
Schematic For Temperature Sender (Intake Manifold Air)

Note: Ensure that the diagnostic code (CID FMI) is on hold. Ensure that the "SERV CODE" indicator is ON. Use the electrical system schematic for the engine that is being serviced to find the connector contact on the main display module. The contact should correspond to the CID that is shown in the Display Area.

This diagnostic code is recorded when the Main Display Module reads a low signal from the sender. As a result of this diagnostic code, the corresponding Gauge Needle moves to the warning region. The following examples are possible causes of a CID 0172 FMI 04.

• The temperature sender (intake manifold air) has a problem.

• The signal circuit of the temperature sender (intake manifold air) is shorted to ground in the engine harness.

• The Main Display Module has a problem.

Note: The main display module is unable to determine the following conditions: an open sender, an open signal from the sender harness and very high resistance on the signal from the sender harness. This condition causes the corresponding Gauge Needle to stay at the left side of the scale.

1. Measure The Resistance Of The Sender.

   1. Turn the "ECS" switch to the OFF/RESET position.

   2. Disconnect the engine harness from the temperature sender (intake manifold air).

   3. Measure the resistance between the two connector contacts of the sender. The correct approximate resistances are listed in the table below.
      Show/hide table

      Table 1

      Resistance Table
      Temperature	Resistance
      25.0 ± 2°C (77.0 ± 3.6°F)	1000 Ohms
      100 ± 2°C (212 ± 3.6°F)	103.7 Ohms

2. Check The Display Area And The Harness.

   1. Turn the "ECS" switch to the OFF/RESET position.

   2. Check for loose terminal contacts on the temperature sender (intake manifold air). Check for loose connections or corroded connections to the temperature sender (intake manifold air).

   3. Replace corroded contacts and tighten loose connections.

   4. Turn the "ECS" switch to the COOLDOWN/STOP position. The "SERV CODE" indicator should be ON forCID 172 FMI 04.

   5. Disconnect the engine harness from the temperature sender (intake manifold air).

   6. Observe the "SERV CODE" indicator.

      Expected Result: The "SERV CODE" indicator should turn OFF.

      Results:

      • OK: The "SERV CODE" indicator turns OFF. The temperature sender (intake manifold air) has a problem. Replace the temperature sender (intake manifold air).

      • Not OK: The "SERV CODE" indicator stays ON. The harness wiring or the Main Display Module has a problem. Proceed to Step 3.

3. Check The Sender Wire For A Short To Ground.

   1. Turn the "ECS" switch to the OFF/RESET position.

   2. Disconnect the engine harness from the temperature sender (intake manifold air).

   3. Turn the "ECS" switch to the COOLDOWN/STOP position.

   4. Measure the voltage of the signal wire for the temperature sender (intake manifold air). The voltage should be measured from pin 1 to pin 2 (ground).

      Expected Result: The voltage should be 6.0 ± 0.5 DCV.

      Results:

      • OK: The voltage is 6.0 ± 0.5 DCV. The voltage is correct. If the "SERV CODE" indicator remains ON, repeat Step 1 through Step 3. If the cause of the diagnostic code is not found, replace the main display module.

      • Not OK: The voltage is less than 0.5 DCV. The harness wiring has a problem. There is an open circuit or a short to ground in the signal wire for the temperature sender. Also, there may be a poorly connected connector.

      • Not OK: The voltage is not greater than 6.5 DCV or less than 0.5 DCV. The harness is shorted to a power circuit. Repair the harness or replace the harness. If the cause of the diagnostic code is not found, replace the Main Display Module.