2007 Liberty KJ Factory Service Manual 9 - ENGINE

P0190-FUEL PRESS SENSOR SIGNAL VOLTAGE TOO LOW





For a complete wiring diagram Refer to Section 8W



Possible Causes
 
FUEL PRESSURE SENSOR
 
FUEL PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
 
FUEL PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO SENSOR GROUND
 
ECM - FUEL PRESSURE SENSOR SIGNAL SHORTED TO GROUND
 




Diagnostic Test

1. CHECKING FOR CURRENT DTC

NOTE: If DTC P0641, P0651 or P0697 is present with this DTC, diagnose DTCs P0641, P0651 or P0697 before diagnosing this DTC.


WARNING: THE FUEL INJECTION PUMP SUPPLIES HIGH-PRESSURE FUEL TO EACH INDIVIDUAL INJECTOR THROUGH HIGH-PRESSURE FUEL LINES. FUEL UNDER HIGH PRESSURE CAN PENETRATE SKIN AND CAUSE PERSONAL INJURY. WEAR SAFETY GOGGLES AND ADEQUATE PROTECTIVE CLOTHING.


NOTE: If the ECM detects and stores a DTC, the ECM also stores the engine/vehicle operating conditions under which the DTC was set. Some of these conditions are displayed on the scan tool at the same time the DTC is displayed.


NOTE: Before erasing stored DTCs, record these conditions. Attempting to duplicate these conditions may assist when checking for an active DTC.


Turn the ignition on.
With the scan tool, erase ECM DTCs.
Cycle the ignition key on and off several times, leaving the key on for at least 10 seconds at a time.
With the scan tool, read ECM DTCs.

Did this DTC set again?

Yes


No

2. FUEL PRESSURE SENSOR



Turn the ignition off.
Disconnect the Fuel Pressure Sensor harness connector.
Turn the ignition on.
Measure the voltage of the Fuel Pressure Sensor Signal circuit.

Is the voltage between 4.7 and 5.3 volts?

Yes


No

3. FUEL PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO GROUND



Turn the ignition off.
Disconnect the Fuel Pressure Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance between ground and the Fuel Pressure Sensor Signal circuit.

Is the resistance above 1000 ohms?

Yes


No

4. FUEL PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO SENSOR GROUND



Measure the resistance between the Fuel Pressure Sensor Ground circuit and the Fuel Pressure Sensor Signal circuit.

Is the resistance above 1000 ohms?

Yes


No

5. ECM - SHORT TO GROUND


If there are no possible causes remaining, view repair.

Repair