C7 Industrial Engine Diagnostic Fault Code List

Use the “DIAGNOSTIC” Lamp or Caterpillar Electronic Technician (ET) in order to determine the diagnostic fault code.

Use the following procedure to retrieve the diagnostic codes if the engine is equipped with a “DIAGNOSTIC” lamp:


  1. Turn the ignition key to the ON position. The engine does not need to be started in order to view codes. The engine does not need to be running while the ignition switch is in the ON position.The “DIAGNOSTIC” lamp blinks on and off at five second intervals.
    • When the ignition key is in the ON position, the lamp is checked for proper operation. If there are any active codes except for Code 34, the codes are displayed at this time.

    Note: The “DIAGNOSTIC” lamp will illuminate for five seconds. The lamp will stay on if there is an active diagnostic code.


  1. The Active Diagnostic codes will always be flashed. There is no toggle switch that will shut off the lamp.


  1. The “DIAGNOSTIC” lamp will flash in order to indicate a two-digit code. The sequence of flashes represents the system diagnostic message. Each digit of the two-digit code is determined by counting the number of flashes. The lamp flashes at a rate of two times per second. The lamp will pause for one second between digits. The lamp will pause for two seconds between codes.

Table 1 indicates the potential effect on the engine performance with active flash codes. Table 1 also forms a list of Electronic diagnostic fault codes and descriptions.

Table 1
Diagnostic Fault/Flash Codes for C7 Industrial Engine
Diagnostic Flash Code Effect On Engine Performance Suggested Action by the Operator
Engine Misfire Low Power Reduced Engine Speed Engine Shut Down Shut down the Engine (1) Service (2) Schedule Service for the Engine. (3)
15 Open or Short Circuit of Injection Actuation Pressure Sensor X X
17 High Injection Actuation Pressure X X
18 Open or Short for the Injection Actuation Pressure Control Valve X X
21 Sensor Supply Voltage Above Normal or Below Normal (4) X X
24 Oil Pressure Sensor Fault (4) X
25 Inlet Manifold Air Pressure Sensor Fault (5) X
26 Atmospheric Pressure Sensor Fault (4) X X
27 Coolant Temperature Sensor Fault (4) X X X
28 Check the Adjustments for the Throttle Position Sensor. X X X
34 Loss Of Engine RPM Signal X X X
35 Event for Engine Overspeed X X
37 Fuel Pressure Sensor Fault (4) X
38 Inlet Manifold Air Temperature Sensor Fault (4) X X X
39 Mechanical Failure of the Injection Actuation Pressure Sensor X X
42 Check the Calibration of the Timing Sensor. X X X X X
46 Low Oil Pressure Event X X X
51 Intermittent Battery Power to the ECM X X X X X
52 Personality Module Fault X X X X X
56 The following parameters must be checked: Customer and System X X X
59 Incorrect Engine Software X X X X
61 Event for High Coolant Temperature X X X X
62 Event for Low Coolant Level X X X X
63 Low Fuel Pressure Event X X X X
64 Even for High Inlet Manifold Air Temperature X X X
72 Fault of Cylinder 1 or Cylinder 2 X X X
73 Fault of Cylinder 3 or Cylinder 4 X X X
74 Fault of Cylinder 5 or Cylinder 6 X X X
( 1 ) Shut down the Engine: Operate the engine cautiously. Get immediate service. Severe engine damage may result.
( 2 ) The operator should go to the nearest location for service.
( 3 ) The operator should investigate the problem at a convenient time.
( 4 ) The Diagnostic Flash Codes reduce the effectiveness of the Engine Monitoring feature.
( 5 ) These Diagnostic Flash Codes may affect the system only under specific environmental conditions such as engine start-up at cold temperatures, etc.

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