C7.1 Industrial Engine and Generator Set Caterpillar

The Electronic Control Module (ECM) monitors the intake manifold air pressure. The following event is associated with low intake manifold air pressure:

Table 1

Code for Low Intake Manifold Air Pressure
J1939 Code	Description	Information
102-18	Engine Intake Manifold #1 Pressure : Low - moderate severity	This pressure is a variable value that is calculated by the ECM. The resulting value is dependent on the operating conditions of the engine.

Probable Causes

• Intake air filter

• Air intake system

• Engine intake throttle valve

• Wastegate regulator

• Low battery voltage

• Turbochargers

Recommended Actions

Intake Air Filter

1. Check the air filter restriction indicator, if equipped.

2. Ensure that the air filter is clean and serviceable.

3. If necessary, replace the air filter element. Refer to the Operation and Maintenance Manual, "Engine Air Cleaner Element - Replace".

4. Check that the fault has been eliminated.

5. If the fault has not been eliminated, proceed to "Air Intake System".

Air Intake System

1. Check the air intake system for the following defects:

   • Blockages

   • Restrictions

   • Damage to the air intake ducts and hoses

   • Loose connections and air leaks

2. Make all necessary repairs to the engine.

3. Ensure that the repairs have eliminated the fault.

4. If the fault has not been eliminated, proceed to "Engine Intake Throttle Valve".

Engine Intake Throttle Valve

1. Use the electronic service tool to check for diagnostic trouble codes that relate to the engine intake throttle valve. Rectify the cause of any related codes. Refer to Troubleshooting, "Diagnostic Trouble Codes".

2. Use the electronic service tool to monitor the function of the engine intake throttle valve. If the valve is not operating correctly, replace the valve. refer to Disassembly and Assembly, "Engine Intake Throttle Valve - Remove and Install".

3. Ensure that the repairs have eliminated the fault.

4. If the fault has not been eliminated, proceed to "Wastegate Regulator".

Wastegate Regulator

1. Use the electronic service tool to check for diagnostic trouble codes that relate to the wastegate regulator. Rectify the cause of any related codes. Refer to Troubleshooting, "Diagnostic Trouble Codes".

2. Ensure that any repairs have eliminated the fault.

3. If the fault has not been eliminated, proceed to "Low Battery Voltage".

Low Battery Voltage

Note: This possible cause of the fault is only applicable to 12 VDC systems. If the application operates with a 24 VDC system, proceed to "Turbochargers".

1. Use a suitable multimeter to check the output voltage from the battery. If the battery voltage is less than 9.75 VDC, refer to the technical communicator at a Caterpillar dealer.

2. If the voltage requirement is not satisfied, refer to Troubleshooting, "Battery Problem".

3. Ensure that any repairs have eliminated the fault.

4. If the fault has not been eliminated, proceed to "Turbochargers".

Turbochargers

Note: The turbochargers that are installed on the engine are nonserviceable items. If any mechanical fault exists, then the faulty turbocharger must be replaced.

1. Check that the compressor housings for the turbochargers are free of dirt and debris.

2. Check that the turbine housings for the turbochargers are free of dirt and debris.

3. Check that the turbine blades rotate freely in the turbochargers.

4. If necessary, replace the faulty turbocharger. Refer to Disassembly and Assembly, "Turbocharger - Remove" and Disassembly and Assembly, "Turbocharger - Install".

5. Check that any repairs have eliminated the fault.

6. If the fault is still present, contact the technical communicator at a Caterpillar dealer.