0127281 JOHNSON KEY, #72

Table 1
Diagnostic Codes Table    
Description    Conditions which Generate this Code    System Response    
94-3 Fuel Delivery Pressure Sensor : Voltage Above Normal     The Electronic Control Module (ECM) detects signal voltage above normal.     The code is logged.
If equipped, the warning light will illuminate.
The ECM will set the delivery pressure for fuel to a default value.    
94-4 Fuel Delivery Pressure Sensor : Voltage Below Normal     The ECM detects signal voltage that is below normal.     The code is logged.
If equipped, the warning light will illuminate.
The ECM will set the delivery pressure for fuel to a default value.    
95-3 Fuel Filter Differential Pressure Sensor : Voltage Above Normal     The ECM detects signal voltage that is above normal.     The code is logged.
If equipped, the warning light will illuminate.    
95-4 Fuel Filter Differential Pressure Sensor : Voltage Below Normal     The ECM detects signal voltage that is below normal.     The code is logged.
If equipped, the warning light will illuminate.    
100-3 Engine Oil Pressure Sensor : Voltage Above Normal     The ECM detects signal voltage above normal for eight seconds.
The engine is not running or coolant temperature is greater than
38 °C (100 °F).     The code is logged.
If equipped, the warning light will illuminate.
The ECM will set engine oil pressure to a default value.    
100-4 Engine Oil Pressure Sensor : Voltage Below Normal     The ECM detects signal voltage below normal for eight seconds.
The engine is running.     The code is logged.
If equipped, the warning light will illuminate.
The ECM will set engine oil pressure to a default value.    
460-3 Fuel Pressure Sensor - After Fuel Filter : Voltage Above Normal     The ECM detects signal voltage that is above normal.     The code is logged.
If equipped, the warning light will illuminate.
The ECM flags the fuel pressure as invalid data.    
460-4 Fuel Pressure Sensor - After Fuel Filter : Voltage Below Normal     The ECM detects signal voltage that is below normal.     The code is logged.
If equipped, the warning light will illuminate.
The ECM flags the fuel pressure as invalid data.    
1785-3 Intake Manifold Pressure Sensor : Voltage Above Normal     The ECM detects signal voltage above normal for two seconds.     The code is logged.
If equipped, the warning light will illuminate.
The ECM will set intake manifold (boost) pressure to a maximum valid pressure for two seconds. The ECM will then set intake manifold (boost) pressure to a default value.    
1785-4 Intake Manifold Pressure Sensor : Voltage Below Normal     The ECM detects signal voltage below normal for two seconds.     The code is logged.
If equipped, the warning light will illuminate.
The ECM will set intake manifold (boost) pressure to a maximum valid pressure for two seconds. The ECM will then set intake manifold (boost) pressure to a default value.    
1797-3 Fuel Rail Pressure Sensor : Voltage Above Normal     The ECM detects signal voltage above normal for two seconds.     The code is logged.
If equipped, the warning light will illuminate.
The engine will be derated.    
1797-4 Fuel Rail Pressure Sensor : Voltage Below Normal     The ECM detects signal voltage below normal for two seconds.     The code is logged.
If equipped, the warning light will illuminate.
The engine will be derated.    The troubleshooting procedures for the diagnostic codes of each pressure sensor are identical. The ECM supplies 5.0 0.2 VDC to terminal "A" of each sensor connector. The sensor return from the ECM connector goes to terminal "B" of each sensor connector. The sensor supply is output short circuit protected. A short circuit to the battery will not damage the circuit inside the ECM.The ECM continuously outputs a pull-up voltage on the circuit for the sensor signal wire. The ECM uses this pull-up voltage in order to detect an open in the signal circuit. When the ECM detects the presence of a voltage that is above a threshold on the signal circuit, the ECM will generate an open circuit diagnostic code -3 for the sensor.If the sensor is disconnected at the sensor connector, the presence of pull-up voltage at the sensor connector indicates that the wires from the sensor connector to the ECM are not open or shorted to ground. If the sensor is disconnected at the sensor connector, the absence of pull-up voltage at the sensor connector indicates an open in the signal wire or a short to ground. If the sensor is disconnected at the sensor connector and the voltage at the sensor connector is different from pull-up voltage, the signal wire is shorted to another wire in the harness.
Illustration 1 g01323297
Typical example of the schematic for the sensors
Illustration 2 g01170309
Typical pressure sensor (1) Voltage supply (2) Sensor return (3) Signal
Illustration 3 g01325134
A typical view of the P2 connector (harness side) pin locations. (38) Intake manifold (boost) pressure sensor return (39) Oil pressure sensor return (40) Fuel rail pressure sensor return (46) Intake manifold (boost) pressure sensor + 5V supply (47) Oil pressure sensor + 5V supply (48) Fuel rail pressure sensor +5V supply (51) Fuel rail pressure sensor signal (55) Intake manifold (boost) pressure sensor signal (56) Oil pressure sensor signal (54) Fuel filter differential pressure sensor signal (50) Fuel pressure sensor signal (39) Fuel filter differential pressure sensor return (38) Fuel pressure sensor return (47) Fuel filter differential pressure sensor + 5V supply (46) Fuel pressure sensor + 5V supply
Illustration 4 g01345581
A typical view of the P2 connector (ECM side) pin locations.Test Step 1. Inspect Electrical Connectors And Wiring.
Turn the keyswitch to the OFF position.
Illustration 5 g01325579
Typical engine ECM (1) J2 ECM connector (2) J1 ECM connector
Thoroughly inspect the terminal connections on the P2/J2 ECM connectors. Thoroughly inspect the connectors for each engine pressure sensor.
Refer to service Troubleshooting, "Electrical Connectors - Inspect".
Perform a 45 N (10 lb) pull test on each of the wires that are associat