DISC 8D1648 - Caterpillar

System Operation Description:Use this procedure to troubleshoot the electrical system if a problem is suspected with one of the sensor supplies. Also, use this procedure if one of the diagnostic codes in Table 1 is active or easily repeated.
Table 1
Diagnostic Codes Table
J1939 Code and Description Conditions that Generate this Code System Response
678-3
ECU 8 Volts DC Supply : Voltage Above Normal The digital sensor supply voltage is above normal for one second. The code is logged.
All affected sensors are set to default values.
678-4
ECU 8 Volts DC Supply : Voltage Below Normal The digital sensor supply voltage is below normal for one second.
3358-21
Engine Exhaust Gas Recirculation Inlet Pressure : Data Drifted Low The ECM detects no 5 VDC supply to the Nox Reduction System (NRS) Engine Exhaust Gas Recirculation Inlet Pressure : Data Drifted Lowabsolute pressure sensor. The code is logged.
3509-3
5 Volt Sensor DC Power Supply : Voltage Above Normal This code indicates that the voltage of the sensor supply is above normal. During normal engine operation, the supply voltage must not exceed 5.16 V. The code is logged.
All affected sensors are set to default values.
3509-4
5 Volt Sensor DC Power Supply : Voltage Below Normal This code indicates that the voltage of the 5 V supply is below normal. During normal engine operation, the 5 V supply must not drop below 4.84 V. The code is logged.
All affected sensors are set to default values.
3510-3
Sensor Supply Voltage 2 : Voltage Above Normal This code indicates that the voltage of sensor supply 2 is above normal. During normal engine operation, the supply voltage must not exceed 5.16 V. The code is logged.
All affected sensors are set to default values.
3510-4
Sensor Supply Voltage 2 : Voltage Below Normal This code indicates that the voltage of the 5 V supply is below normal. During normal engine operation, the 5 V supply must not drop below 4.84 V. The code is logged.
All affected sensors are set to default values.
3563-21
Engine Intake Manifold #1 Absolute Pressure : Data Drifted Low
Left -hand sensor The ECM detects no 5 V supply to the intake manifold pressure sensor #1. The code is logged.
5422-21
Engine Intake Manifold #2 Absolute Pressure : Data Drifted Low
Right -hand sensor The ECM detects no 5 V supply to the intake manifold pressure sensor #2. The code is logged. System OperationThe Electronic Control Module (ECM) supplies a regulated voltage of 5.0 0.2 VDC to the following sensors:
Engine oil pressure sensor
Barometric pressure sensor
Crankcase pressure sensor
Intake manifold pressure sensor #1 (left-hand)
Intake manifold pressure sensor #2 (right-hand)
NRS absolute pressure sensor
Fuel pressure sensor before the filter
Fuel pressure sensor after the filter
NRS delta pressure sensor
Auxiliary #1 Pressure SensorThe ECM supplies a regulated voltage of 8.0 0.4 VDC to each of the throttle position 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 -21 code becomes active when the ECM determines that the 5 V