Page 529 of 5267

When Monitored:
With the ignition on and battery voltage greater than 10.4 volts.
Set Condition:
The circuit voltage to the ECM falls below a calibrated threshold for a certain period of time.
Possible Causes
OTHER DTC’S
FUEL PRESSURE SENSOR
(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO (F855) RETURN CIRCUIT
(K181) SIGNAL CIRCUIT SHORTED TO (F855) RETURN CIRCUIT
(K181) SIGNAL CIRCUIT OPEN
(F855) 5-VOLT SUPPLY CIRCUIT OPEN
(K181) SIGNAL CIRCUIT SHORTED TO GROUND
(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
ECM
INTERMITTENT CONDITION
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.OTHER DTC’S
Ignition on, engine not running.
With the scan tool, read DTCs.
Do you have multiple DTC’s?
Ye s>>
Repair other DTC’s first.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 2
2.(F855) 5-VOLT SUPPLY AND (K915) RETURN CIRCUIT
Turn the ignition off.
Disconnect the Fuel Pressure sensor harness connector.
NOTE: Check connectors - Clean/repair as necessary.
Ignition on, engine not running.
Measure the voltage between the (F855) 5-volt supply and (K915)
return circuits of the Fuel pressure sensor harness connector.
Is the voltage between 4.5 and 5.5 volts?
Ye s>>
Go To 3
No>>
Go To 4
Page 530 of 5267

3.FUEL PRESSURE SENSOR
Reconnect the disconnected Fuel Pressure Sensor harness connector.
While monitoring scan tool, disconnect the Fuel Pressure sensor harness connector.
Does the DTC P0193 set?
Ye s>>
Replace the Fuel Pressure Sensor.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 4
4.(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO (K915) RETURN CIRCUIT
Turn the ignition off.
Disconnect the ECM harness connectors.
Disconnect the Fuel Pressure sensor harness connector.
Check connectors - Clean/repair as necessary.
Measure the resistance between the (F855) 5-volt supply circuit and
(K915) return circuit in the sensor harness connector.
Is the resistance greater than 100 K Ohms?
Ye s>>
Go To 5
No>>
Repair the shorted circuits.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
5.(K181) SIGNAL CIRCUIT SHORTED TO (K915) RETURN CIRCUIT
Measure the resistance between the (K181) signal circuit and (K915)
return circuit in the sensor connector.
Is the resistance greater than 100 K Ohms?
Ye s>>
Go To 6
No>>
Repair the shorted circuits.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
Page 531 of 5267
6.(K181) SIGNAL CIRCUIT OPEN
Measure the resistance between the signal (K181) circuit in the sensor
harness connector with the (K181) signal circuit in the ECM harness
connector.
Is the resistance less than 10 Ohms?
Ye s>>
Go To 7
No>>
Repair the open (K181) signal circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
7.(F855) 5-VOLT SUPPLY CIRCUIT OPEN
Measure the resistance between the supply (F855) circuit in the sensor
harness connector with the (F855) 5-volt supply circuit in the ECM har-
ness connector.
Is the resistance less than 10 Ohms?
Ye s>>
Go To 8
No>>
Repair the open (F855) 5-volt supply circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
Page 532 of 5267

8.(K181) SIGNAL CIRCUIT SHORTED TO GROUND
Measure the resistance between the (K181) signal circuit in the sensor
harness connector and battery negative.
Is the resistance greater than 100 K Ohms?
Ye s>>
Go To 9
No>>
Repair (K181) signal circuit shorted to ground.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
9.(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
Measure the resistance between the (F855) 5-volt supply circuit in the
sensor harness connector and battery negative.
Is the resistance greater than 100 K Ohms?
Ye s>>
Go To 10
No>>
Repair (F855) 5-volt Supply circuit shorted to ground.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
10.ECM
Reconnect the disconnected Fuel pressure sensor harness connector and ECM harness connectors.
While monitoring scan tool, disconnect the Fuel Pressure sensor connector.
Does the DTC P0193 set?
Ye s>>
Te s t C o m p l e t e .
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Replace the ECM.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Page 533 of 5267
P0193-FUEL PRESSURE SENSOR VOLTAGE TOO HIGH
For a complete wiring diagramRefer to Section 8W.
Page 534 of 5267

When Monitored:
With the ignition on and battery voltage greater than 10.4 volts.
Set Condition:
The circuit voltage to the ECM is above a calibrated threshold for a certainperiod of time.
Possible Causes
OTHER DTC’S
FUEL PRESSURE SENSOR
(K181) SIGNAL CIRCUIT SHORTED TO VOLTAGE
(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
(K181) SIGNAL CIRCUIT SHORTED TO (F855) 5-VOLT SUPPLY CIRCUIT
(K915) RETURN CIRCUIT OPEN
ECM
INTERMITTENT CONDITION
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.OTHER DTC’S
Ignition on, engine not running.
With the scan tool, read DTCs.
Do you have multiple DTC’s?
Ye s>>
Refer to multiple fault troubleshooting tree.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 2
2.(F855) 5-VOLT SUPPLY AND (K915) RETURN CIRCUIT
Turn the ignition off.
Disconnect the Fuel Pressure sensor harness connector.
NOTE: Check connectors - Clean/repair as necessary.
Ignition on, engine not running.
Measure the voltage between the (F855) 5-volt supply and (K915)
return circuits of the Fuel pressure sensor harness connector.
Is the voltage between 4.5 and 5.5 volts?
Ye s>>
Go To 3
No>>
Go To 4
Page 535 of 5267

3.FUEL PRESSURE SENSOR
While monitoring scan tool, connect a jumper wire between the (K181)
signal circuit and the (K915) return circuit of the Fuel Pressure sensor
connector.
Does the DTC P0192 set?
Ye s>>
Replace the Fuel Pressure Sensor.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
No>>
Go To 4
4.(K181) SIGNAL CIRCUIT SHORTED TO VOLTAGE
Turn the ignition off.
Disconnect the Fuel Pressure sensor harness connector.
Disconnect the ECM harness connectors.
Check connectors - Clean/repair as necessary.
Turn the ignition on.
Measure the voltage between the (K181) signal circuit of the sensor
harness connector and battery negative.
Is the voltage less than 1 volt?
Ye s>>
Go To 5
No>>
Repair the (K181) signal circuit shorted to voltage.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
5.(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
Measure the voltage between the (F855) 5-volt supply circuit of the sen-
sor harness connector and battery negative.
Is the voltage less than 1 volt?
Ye s>>
Go To 6
No>>
Repair the (F855) 5-volt supply circuit shorted to voltage.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
Page 536 of 5267
6.(K181) SIGNAL CIRCUIT SHORTED TO (F855) 5-VOLT SUPPLY CIRCUIT
Turn the ignition off.
Measure the resistance between the (K181) signal circuit and (F855)
5-volt supply circuit in the sensor connector.
Is the resistance greater than 10 K Ohms?
Ye s>>
Go To 7
No>>
Repair the shorted circuits.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
7.(K915) RETURN CIRCUIT OPEN
Measure the resistance between the (K915) return circuit in the sensor
harness connector with the (K915) return circuit in the ECM harness
connector.
Is the resistance less than 10 Ohms?
Ye s>>
Go To 8
No>>
Repair the open (K915) return circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)