GASKET 2A4572 - Caterpillar

Use this procedure to troubleshoot the electrical system if a problem is suspected with a sensor supply. Also, use this procedure if one of the following diagnostic codes is active or easily repeated.
Table 1
J1939 Code and Description CDL Code and Description Comments
108-21
Barometric Pressure : Data Drifted Low 3528-21
Barometric Pressure Sensor : Data Drifted Low The code is logged.
678-3
ECU 8 Volts DC Supply : Voltage Above Normal 41-3
8 Volt DC Supply : Voltage Above Normal The code is logged.
678-4
ECU 8 Volts DC Supply : Voltage Below Normal 41-4
8 Volt DC Supply : Voltage Below Normal The code is logged.
3509-3
Sensor Supply Voltage 1 : Voltage Above Normal 262-3
5 Volt Sensor DC Power Supply : Voltage Above Normal All sensors are set to default values.
The code is logged.
3509-4
Sensor Supply Voltage 1 : Voltage Below Normal 262-4
5 Volt Sensor DC Power Supply : Voltage Below Normal All sensors are set to default values.
The code is logged.
3510-3
or Supply Voltage 2 : Voltage Above Normal 2131-3
5 Volt Sensor DC Power Supply #2 : Voltage Above Normal Engine power may be derated.
The code is logged.
3510-4
Sensor Supply Voltage 2 : Voltage Below Normal 2131-4
5 Volt Sensor DC Power Supply #2 : Voltage Below Normal Engine power may be derated.
The code is logged.
3563-21
Engine Intake Manifold #1 Absolute Pressure : Data Drifted Low 1785-21
Intake Manifold Pressure Sensor : Data Drifted Low The code is logged.
5422-21
Engine Intake Manifold #2 Absolute Pressure : Data Drifted Low 3031-21
Intake Manifold #2 Pressure Sensor : Data Drifted Low The code is logged.
5580-21
Engine Filtered Fuel Delivery Absolute Pressure : Data Drifted Low 460-21
Fuel Pressure Sensor - After Fuel Filter : Data Drifted Low The 5 VDC supply to the sensor has been lost.
The code is logged. The Electronic Control Module (ECM) supplies a regulated voltage of 5.0 0.2 VDC to the sensors.The supply voltage for the sensors is routed from the ECM to terminal 1 of each sensor connector. The sensor return for the sensors is routed from the ECM to terminal 2 of each sensor connector. The ECM provides short circuit protection for the internal power supply. A short circuit to the battery will not damage the internal power supply.Note: The sensors are not protected from overvoltage. A short from the supply line to the +Battery may damage the sensors. If any of the diagnostic codes are active, a sensor may have been damaged. Repair the sensor supply and check for any active sensor diagnostic codes to determine if a sensor has been damaged.Refer to the application-specific wiring schematic for pin locations.
Table 2
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Determine if a code is active or logged.
Codes
Result: A -3 or -4 code is active. Note which ECM is reporting the active code.
Proceed to Test Step 2.
Result: A -21 code is active.
Proceed to Test Step 3.
2. Check for a Failed Sensor
A. Connect Cat ET.
B. Disconnect a sensor on the affected sensor supply circuit.
C. Use Cat ET to monitor following:
- Active code changes