Intake Manifold Air Pressure Is Low
This procedure covers the following diagnostic code:
Show/hide table
Diagnostic Trouble Codes for Low Intake Manifold Air Pressure | ||
J1939 Code | Description | Notes |
1127-18 | Engine Turbocharger 1 Boost Pressure : Low - moderate severity (2) | The Electronic Control Module (ECM) detects the following conditions: The actual intake manifold air pressure is less than the desired intake manifold air pressure for at least 10 seconds. The difference between the two values depends on engine operating conditions. The engine speed is between 1000 rpm and 2300 rpm. The engine coolant temperature is greater than There are no active 102 diagnostic codes for the intake manifold air pressure sensor. There is no other active engine derates. If equipped, the warning lamp will flash. The engine will be derated. The fault will be cleared when the intake manifold air pressure is within the acceptable range for at least 11 minutes. |
- Intake air filter
- Air intake system
- Wastegate regulator
- Turbocharger
Note: The procedures have been listed in order of probability. Complete the procedures in order.
Show/hide table
Troubleshooting Test Steps | Values | Results |
---|---|---|
1. Intake Air Filter A. Check the air filter restriction indicator, if equipped. B. Ensure that the air filter is clean and serviceable. |
Air filter |
Result: The air filter is blocked. Repair: Replace the air filter element. Refer to the Operation and Maintenance Manual, "Engine Air Cleaner Element - Replace". Result: The air filter is OK. Proceed to Test Step 2. |
2. Air Intake System A. Check the air intake system for the following defects: · Blockages · Restrictions · Damage to the air intake ducts and hoses · Loose connections and air leaks |
Air intake |
Result: The air intake system is blocked, restricted, damaged, or loose. Repair: Make all necessary repairs to the air intake system. Result: The air intake system is OK. Proceed to Test Step 3. |
3. Wastegate Regulator A. Use the electronic service tool to check for diagnostic trouble codes that relate to the wastegate regulator. |
Wastegate regulator |
Result: Diagnostic codes are present that relate to the wastegate regulator. Repair: Rectify the cause of any related codes. Refer to Troubleshooting, "Diagnostic Trouble Codes". Result: There are no diagnostic codes that relate to the wastegate regulator. Proceed to Test Step 4. |
4. Turbocharger Note: The turbocharger that is installed on the engine is a nonserviceable item. If any mechanical fault exists, then the turbocharger must be replaced. A. Check that the compressor housings for the turbochargers are free of dirt and debris. B. Check that the turbine housings for the turbochargers are free of dirt and debris. C. Check that the turbine blades rotate freely in the turbochargers. |
Turbocharger |
Result: There is a fault with the turbocharger. Repair: Replace the turbocharger. Refer to Disassembly and Assembly, "Turbocharger - Remove" and Disassembly and Assembly, "Turbocharger - Install". Result: The turbocharger is OK. Contact the Dealer Solution Network (DSN). |
Caterpillar Information System:
C32 Marine Engine Cat Data Link - Test
C9.3B Engines for Caterpillar Built Machines Fuel Filter Base - Remove and Install
C32 Marine Engine CAN Data Link - Test
C8.7 and C12.9 Marine Engines Fuel Consumption Is Excessive
C8.7 and C12.9 Marine Engines Exhaust Has Excessive Black Smoke
C8.7 and C12.9 Marine Engines Acceleration Is Poor or Throttle Response Is Poor
C9.3B Engines for Caterpillar Built Machines Fuel Manifold (Rail) - Remove and Install
795F AC and 795F AC XQ Off-Highway Truck Machine Systems Electric Retarder - Assemble - Grid Assembly
Cylinder Block Cleaning and Audit Procedure {0644, 0680, 0701} Cylinder Block Cleaning and Audit Procedure {0644, 0680, 0701}
C175 Tier 4 Final Engines for Caterpillar Built Machines Engine Oil Screen - Remove and Install
C8.7 and C12.9 Marine Engines Electronic Service Tools
Connector Identification, Removal, Disassembly, Reassembly, and Installation for All Cat® Products Equipped with BR Series Connectors {1408} Connector Identification, Removal, Disassembly, Reassembly, and Installation for All Cat® Products Equipped with BR Series Connectors {1408}
C175-20 Locomotive Engine Emissions Certification Film
C32 Marine Engine Coolant Level - Test
C32 Marine Engine Indicator Lamp - Test
C32 Marine Engine Sensor Signal (Analog, Active) - Test
C32 Marine Engine Sensor Signal (Analog, Passive) - Test
C32 Marine Engine Sensor Signal (PWM) - Test
C32 Marine Engine Sensor Supply - Test
C32 Marine Engine Speed Control - Test
C9.3B Engines for Caterpillar Built Machines Front Cover - Remove and Install
C32 Marine Engine Speed/Timing - Test
C32 Marine Engine Switch Circuits - Test
C32 Marine Engine Synchronization - Test