0512743 JOHNSON RETAINER, 4 terminal

Table 1
Diagnostic Codes Table
Description Conditions which Generate this Code System Response
94-3 Engine Fuel Delivery Pressure : Voltage Above Normal The Electronic Control Module (ECM) detects signal voltage that is above normal for one second.
The ECM has been powered for at least 3 seconds. The code is logged.
94-4 Engine Fuel Delivery Pressure : Voltage Below Normal The ECM detects signal voltage that is below normal for one second.
The ECM has been powered for 3 seconds.
100-3 Engine Oil Pressure : Voltage Above Normal The ECM detects signal voltage that is above normal for one second.
The ECM has been powered for at least 3 seconds. The code is logged.
100-4 Engine Oil Pressure : Voltage Below Normal The ECM detects signal voltage that is below normal for one second.
The ECM has been powered for 3 seconds.
101-3 Engine Crankcase Pressure : Voltage Above Normal The ECM detects signal voltage that is above normal for one second.
The ECM has been powered for at least 3 seconds. The code is logged.
101-4 Engine Crankcase Pressure : Voltage Below Normal The ECM detects signal voltage that is below normal for one second.
The ECM has been powered for at least 3 seconds.
273-3 Turbo Outlet Pressure : Voltage Above Normal The ECM detects signal voltage that is above normal for one second.
The ECM has been powered for at least 3 seconds. The code is logged.
273-4 Turbo Outlet Pressure : Voltage Below Normal The ECM detects signal voltage that is below normal for one second.
The ECM has been powered for 3 seconds.
274-3 Atmospheric Pressure : Voltage Above Normal The ECM detects signal voltage that is above normal for one second.
The ECM has been powered for at least 3 seconds. The code is logged.
274-4 Atmospheric Pressure : Voltage Below Normal The ECM detects signal voltage that is below normal for one second.
The ECM has been powered for 3 seconds.
275-3 Right Turbo Inlet Pressure : Voltage Above Normal The ECM detects signal voltage that is above normal for one second.
The ECM has been powered for at least 3 seconds. The code is logged.
275-4 Right Turbo Inlet Pressure : Voltage Below Normal The ECM detects signal voltage that is below normal for one second.
The ECM has been powered for 3 seconds.
276-3 Left Turbo Inlet Pressure open/short to +batt The ECM detects signal voltage that is above normal for one second.
The ECM has been powered for at least 3 seconds. The code is logged.
276-4 Left Turbo Inlet Pressure short to ground The ECM detects signal voltage that is below normal for one second.
The ECM has been powered for 3 seconds.
279-3 Aftercooler Temperature open/short to +batt The ECM detects signal voltage that is above normal for one second.
The ECM has been powered for at least 3 seconds. The code is logged.
279-4 Aftercooler Temperature short to ground The ECM detects signal voltage that is below normal for one second.
The ECM has been powered for 3 seconds.
542-3 Unfiltered Engine Oil Pressure open/short to +batt The ECM detects signal voltage that is above normal for one second.
The ECM has been powered for at least 3 seconds. The code is logged.
542-4 Unfiltered Engine Oil Pressure short to ground The ECM detects signal voltage that is below normal for one second.
The ECM has been powered for 3 seconds. System OperationUse this procedure to troubleshoot any suspect problems with the following sensors for the primary and/or secondary ECM:
Aftercooler temperature sensor
Atmospheric pressure sensor
Coolant temperature sensor
Crankcase pressure sensor
Filtered engine oil pressure sensor
Filtered fuel pressure sensor
Turbocharger outlet pressure sensor
Left turbocharger inlet pressure sensor
Right turbocharger inlet pressure sensor
Unfiltered engine oil pressure sensor
Unfiltered fuel pressure sensorBackground InformationThe ECM performs an automatic calibration of these sensors whenever the ECM is powered and the engine is off for at least 5 seconds. During an automatic calibration, the ECM calibrates pressure sensors to the value of the atmospheric pressure sensor and against an acceptable offset pressure range.The ECM continuously creates a pull-up voltage on the signal wire for each sensor. The ECM uses this pull-up voltage in order to detect a problem in the signal circuit. When the ECM detects voltage that is above a threshold on the signal wire, the ECM activates a high voltage -3 diagnostic code. When the ECM detects voltage that is below a threshold on the signal wire, the ECM activates a low voltage -4 diagnostic code.Note: There may be a delay of 30 seconds in order for Caterpillar Electronic Technician (ET) to display an active diagnostic code. When you check for a diagnostic code, be sure to wait at least 30 seconds.The following components can cause these codes:
Electrical connector or wiring
Sensor
ECMThe most likely cause of a code is a problem with an electrical connector or wiring. The least likely cause of a code is the ECM.
Illustration 1 g03317117
Analog active sensor schematic
Illustration 2 g03321053
Terminal locations at the P1 ECM connectors for the analog sensors
(P1-2) Analog supply
(P1-3) Analog return
(P1-16) Filtered oil pressure
(P1-17) Unfiltered oil pressure
(P1-24) Filtered fuel pressure
(P1-25) Unfiltered fuel pressure
(P1-35) Analog return
(P1-39) Analog supply
Illustration 3 g03321404
Terminal locations at the P2 ECM connector for the analog sensors
(P2-36) Turbo outlet pressure
(P2-37) Atmospheric pressure
(P2-38) Left turbo inlet pressure
(P2-39) Right turbo inlet pressure
(P2-46) Crankcase pressure
Illustration 4 g01240891
Sensor connector
(Terminal 1) Sensor supply
(Terminal 2) Sensor return
(Terminal 3) Signal
Table 2
Troubleshooting Test Steps Values Results
1. Determine if the Code is Logged or Active
A. Connect Cat ET to the service tool connector.
B. Restore electrical power to the engine ECM.
C. Monitor the active diagnostic code and the logged diagnostic codes on Cat ET.
Note. Wait at least 30 seconds in order for diagnostic codes to become active.
D. Identify the diagnostic code