Caterpillar Monitoring System for Electronic Modular Control Panel Caterpillar

Illustration 1	g00640186
Schematic Of The Inlet Air (Boost) Pressure Sensor

Note: Ensure that the desired diagnostic code is on hold. Ensure that the "SERV CODE" indicator is on. Use the electrical system schematic for the engine that is being serviced in order to find the connector contact on the Main Display Module which corresponds to the current CID.

The diagnostic code is recorded when the Main Display Module reads the sensor signal and the module determines that the signal is abnormal.

The following examples are possible causes of this diagnostic code:

• The inlet air pressure sensor (boost) has a problem.

• The ground circuit of the inlet air pressure sensor (boost) is open in the engine harness.

• The signal circuit of the inlet air pressure sensor (boost) is shorted to +battery in the engine harness.

• The signal circuit of the inlet air pressure sensor (boost) is open or the connector is disconnected.

• The Main Display Module has a problem.

1. Check Readout and Harness.

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

   2. Check for loose connections or for corroded terminal connections to the inlet air pressure sensor (boost). Clean the corroded terminals and tighten the loose connections.

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

   4. The "SERV CODE" indicator should be on for the CID 0102 FMI 08 diagnostic code.

      Expected Result: The SERV CODE indicator should be on for the CID 0102 FMI 08 diagnostic code.

      Results:

      • YES - The SERV CODE indicator shows CID 0102 FMI 08. Go to 2

      • NO - The SERV CODE indicator does not show CID 0102 FMI 08. The diagnostic code does not exist at this time. The initial problem was probably caused by a loose connection in the machine harness. STOP.

2. Measure Inlet Air Pressure Sensor (Boost) Supply Wire.

   1. Turn the ECS to the COOLDOWN/STOP position.

   2. At the oil pressure sensor, use the 7X-1710 Multimeter Probe and measure the voltage from the ground wire (contact B) to the supply wire (contact A).

      Expected Result: The voltage is 8.0 ± 0.5 DCV.

      Result:

      • YES - The voltage is 8.0 ± 0.5 DCV. The voltage is correct. Go to 3.

      • NO - The voltage is less than 0.5 DCV. The harness wiring has a problem. There is an open circuit, a short to ground in the supply wire for the inlet air pressure sensor (boost), or a poor connection. Repair the harness or replace the harness. If the cause of the diagnostic code is not found, go to 3.

3. Measure Inlet Air Pressure Sensor (Boost) Signal Voltage.

   1. Turn the ECS to the COOLDOWN/STOP position.

   2. At the oil pressure sensor, use the 7X-1710 Multimeter Probe and measure the voltage from the ground wire (contact B) to the supply wire (contact A).

      Expected Result: The voltage is between 1.0 and 7.0 volts.

      Results:

      • YES - The voltage is between approximately 1.0 and 7.0 DCV. The signal voltage at the sensor is correct. Go to 4.

      • NO - The voltage is not between approximately 1.0 and 7.0 DCV. The signal voltage at the sensor is not correct. If the voltage is greater than 7.0 DCV, go to 5. If the voltage is less than 1.0 DCV, go to 6.

4. Measure Engine Oil Pressure Signal Voltage.

   1. Turn the ECS to the COOLDOWN/STOP position.

   2. Use the 7X-1710 Multimeter Probe and measure the voltage from the Main Display Module's contact for the ground wire to the contact for the signal wire.

      Expected Result: The voltage is identical to the voltage that was recorded in Step 3.

      Results:

      • YES - The voltage is identical to the voltage that was recorded in Step 3. The Main Display Module is receiving a valid signal voltage. The Main Display Module has a problem. Replace the Main Display Module. See Testing And Adjusting, "Module - Replace" for more information.

      • NO - The Voltage is not the same as in 3. The engine harness has an open circuit in the signal circuits or ground circuits. Repair the engine harness or replace the engine harness.

5. Check for Short to +Battery.

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

   2. Disconnect the connector for the Main Display Module and disconnect the connector for the inlet air pressure sensor (boost).

   3. Use the 7X-1710 cable probes and measure the resistance between +battery and the signal wire (contact C) for the inlet air pressure sensor (boost).

      Expected Result: The resistance is greater than 5000 ohms.

      Results:

      • YES - The resistance is greater than 5000 ohms. The harness signal wire is correct. Replace the Main Display Module. See Testing And Adjusting, "Module - Replace" for more information.

      • NO - The resistance is less than 5000 ohms. Repair the harness or replace the harness.

6. Check for Short to Ground.

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

   2. Disconnect the connector for the Main Display Module and disconnect the connector for the inlet air pressure sensor (boost).

   3. Use the 7X-1710 cable probes and measure the resistance between ground and the signal wire (contact C) for the inlet air pressure sensor (boost).

      Expected Result: The resistance is greater than 5000 ohms.

      Results:

      • YES - The resistance is greater than 5000 ohms. The harness signal wire is correct. Replace the Main Display Module. See Testing And Adjusting, "Module - Replace" for more information.

      • NO - The resistance is less than 5000 ohms. Repair the harness or replace the harness.