C7.1 Engines Caterpillar

Intake Manifold Air Pressure Is Low

Usage:

C7.1 881

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

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Table 1
Diagnostic Trouble Code for Low Intake Manifold Air Pressure
J1939 Code	CDL Code	Code Description (Code descriptions may vary)	Comments
102-18	E1045 (2)	Engine Intake Manifold #1 Pressure : Low - moderate severity (2)	The pressure to trip this diagnostic code is a variable value that is calculated by the ECM. The resulting value depends on the operating conditions of the engine.

Probable Causes

Intake air filter
Air intake system
Wastegate regulator
Low battery voltage
Turbocharger or turbochargers
Turbocharger wastegate

Recommended Actions

Note: The procedures have been listed in order of probability. Complete the procedures in order.

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Table 2
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 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. 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 Test Step 5 or Test Step 6, as applicable. A. Use a suitable multimeter to check the output voltage from the battery or batteries.	Turbocharger	Result: The battery voltage is less than 9.75 VDC. Repair: The voltage requirement is not satisfied. Refer to Troubleshooting, "Battery Problem". Ensure that any repairs have eliminated the fault. Result: The battery voltage is OK. For engines that have a single turbocharger, proceed to Test Step 5. For engines that have two turbochargers, proceed to Test Step 6.
5. Turbocharger Note: The turbocharger that is installed on the engine is a nonserviceable item. If any mechanical fault exists, then the faulty turbocharger must be replaced. A. Check that the compressor housing for the turbocharger is free of dirt and debris. B. Check that the turbine housing for the turbocharger is free of dirt and debris. C. Check that the turbine blades rotate freely in the turbocharger.	Turbocharger	Result: There is a fault in the turbocharger. Repair: Replace the turbocharger. Refer to Disassembly and Assembly, "Turbocharger - Remove" and Disassembly and Assembly, "Turbocharger - Install". Result: The turbocharger is OK. Proceed to Test Step 7.
6. 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. 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.	Turbochargers	Result: There is a fault in a turbocharger. Repair: Replace the faulty turbocharger. Refer to Disassembly and Assembly, "Turbocharger - Remove" and Disassembly and Assembly, "Turbocharger - Install". Result: The turbochargers are OK. Proceed to Test Step 7.
7. Turbocharger Wastegate Note: On engines with a single turbocharger, the wastegate is attached to the turbocharger. On engines with twin turbochargers, the wastegate is attached to the high-pressure turbocharger. A. Check the operation of the wastegate on the turbocharger. B. Check the operation of the wastegate actuator on the turbocharger. Refer to Systems Operation, Testing, and Adjusting, "Turbocharger - Inspect" and Special Instruction, M0084071, "Turbocharger Wastegate Actuator on Certain C7.1 Engines".	Turbocharger wastegate	Result: Operation of the turbocharger wastegate is suspect. Repair: Disconnect the output rod in the wastegate actuator from the lever that operates the wastegate. Operate the wastegate lever by hand and check for full and free movement. Check that the output rod in the wastegate actuator is biased towards the retracted position. Connect the output rod in the wastegate actuator to the lever that operates the wastegate. If the wastegate is not operating correctly, replace the turbocharger. Refer to Disassembly and Assembly, "Turbocharger - Remove" and Disassembly and Assembly, "Turbocharger - Install". Result: There is a suspected fault in the wastegate or the wastegate actuator. Repair: Replace the turbocharger. Refer to Disassembly and Assembly, "Turbocharger - Remove" and Disassembly and Assembly, "Turbocharger - Install". Result: The wastegate and the wastegate actuator operate correctly. Contact the Dealer Solutions Network (DSN).