DISC 8E6931 - Caterpillar

System Operation Description:Use this procedure to troubleshoot the system when one of the following diagnostic codes is active or easily repeated:
0262-03 5 Volt Sensor DC Power Supply voltage above normal
0262-04 5 Volt Sensor DC Power Supply voltage below normalThe following background information is related to this procedure:The Engine Control Module (ECM) supplies regulated +5 Volts DC to the following sensors:
Fuel Rail Pressure Sensor through connector P228
Intake Manifold Pressure Sensor through connector P200
Engine Oil Pressure Sensor through connector P201
Analog Throttle Demand Sensors (if equipped) through P1 connectorThe supply for the +5 Volt engine pressure sensor is routed from the ECM through the P2 connector to terminal 1 of each pressure sensor connector. The supply voltage is 5.0 0.16 Volts DC. The +5 Volt supply to the Analog Throttle Demand Sensor is routed from the ECM through the P1 connector to the sensor pins "A".A diagnostic code can be caused by the following conditions:
A short circuit in the harness
An open circuit in the harness
A suspect sensor
A suspect ECM
Table 1
P2 Pin Connections    
Sensor Pin     Function     Fuel Rail Pressure Sensor     Intake Manifold Pressure Sensor     Oil Pressure Sensor    
1     Volts (5V)     48     46     47    
2     Ground     40     38     39    
3     Signal     51     55     56    
Table 2
P1 OEM Connector    
Sensor Pin     Function     Analog Throttle 1     Analog Throttle 2    
A     5 Volt Sensor Supply     41     42    
B     Ground     33     34    
C     Signal     54     55    
Illustration 1 g01800518
Typical example of the schematic for the sensors
Illustration 2 g01173224
Typical example of the fuel rail pressure sensor (1) Voltage supply (Vs) (2) Ground (GND) (3) Signal (SIG)
Illustration 3 g01173225
Typical example of the intake manifold pressure sensor (1) Voltage Supply (Vs) (2) Ground (GND) (3) Signal (SIG)
Illustration 4 g01173226
Typical example of the oil pressure sensor (1) Voltage Supply (Vs) (2) Ground (GND) (3) Signal (SIG)
Illustration 5 g01800553
Typical example of the P2 pressure sensor pin locations (38) Ground (GND) Intake Manifold Pressure Sensor (39) Ground (GND) Oil Pressure Sensor (40) Ground (GND) Fuel Rail Pressure Sensor (46) Voltage supply (5V) Intake Manifold Pressure Sensor (47) Voltage supply (5V)) Oil Pressure Sensor (48) Voltage supply (5V) Fuel Rail Pressure Sensor (51) Signal (SIG) Fuel Rail Pressure Sensor (55) Signal (SIG) Intake Manifold Pressure Sensor (56) Signal (SIG) Oil Pressure Sensor
Illustration 6 g01800573
Typical example of the P1 pin locations for the analog throttle demand sensor (33) Throttle 1 ground (GND) (34) Throttle 2 ground (GND) (41) Throttle 1 voltage supply (5V) (42) Throttle 2 voltage supply (5V) (54) Throttle 1 throttle position (55) Throttle 2 throttle position
Illustration 7 g01800596
Typical example of the schematic for the P1 connections for the analog throttle demand sensors Test Step 1. Check for Connector Damage
Turn the keyswitch to the OFF position.
Check the connectors and the harness for the following faults:
Damage
Abrasion
Corrosion
Incorrect attachment
Refer to Troubleshooting, "Electrical Connectors - Inspect".
Perform a 45 N (10 lb) pull test on each