Diagnostic Test

WARNING: This page is about a different car, the 2017 Jeep Patriot and 2017 Jeep Compass. However, it is still accessible from the selected car via links, so may be relevant.

CHECK FUEL DELIVERY SYSTEM FOR LEAKS AND DAMAGE
WARNING:
The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting, or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.
1. Visually and physically inspect the fuel delivery system for external leaks and damage.
  Is the system leaking or damaged?
  
  Yes
  - Repair / replace as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 2
INSTALL APPROPRIATE FUEL LINE ADAPTERS / FITTING FROM GAS AND DIESEL FUEL PRESSURE/DECAY TESTER 8978A

Courtesy of CHRYSLER GROUP, LLC
1. Turn the ignition off.
  WARNING:
  The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting, or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.
2. Disconnect the frame rail fuel supply line connector between the fuel supply line and the fuel rail.
3. Install the appropriate Fuel Line Adapters / Fitting from Gas and Diesel Fuel Pressure/Decay Tester (special tool #8978A, Decay Tool, Fuel).
  Proceed
  - Go To 3
INSTALL FUEL PRESSURE GAUGE ASSEMBLY

Courtesy of CHRYSLER GROUP, LLC

WARNING:
The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting, or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.
1. Connect Gas and Diesel Fuel Pressure/Decay Tester (special tool #8978A, Decay Tool, Fuel), Fuel Inlet Hose (1) and Fuel Outlet Hose (2) to the Fuel Line Adapters / Fitting.
2. Connect Drain Extension Hose 535680 (3) to the Fuel Pressure Gauge Assembly Drain Hose (5).
3. Connect the Reservoir Assembly 534960 (4) to the Drain Extension Hose 535680 (3).
  WARNING:
  To reduce the risk of fire and serious possible serious or fatal injury, place Reservoir Assembly 534960 (4) on the floor and out of the way so that it is not a trip hazard.
  
  Proceed
  - Go To 4
CHECK FUEL PRESSURE

Courtesy of CHRYSLER GROUP, LLC

WARNING:
The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting, or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.
1. Perform the following procedure to purge air from the system:
  - Open the Fuel System Isolation Valve (1).
  - Close the Flow Test Valve (2).
  - Ignition on, engine not running.
  - With the scan tool, actuate the fuel pump.
  - Open the Flow Test Valve (1) for 10 seconds, then close the Valve.
  - CAUTION: Stop All Actuations.
  - Turn the ignition off.
  - Disconnect, empty and then reconnect the Reservoir Assembly.
2. Turn the ignition on, wait five seconds, turn the ignition off and then wait 1 minute before proceeding.
3. Read the Fuel Pressure Gauge (3) and record the reading.
4. The fuel pressure specification is 407 kPa +/- 34 kPa (59 psi +/- 5 psi).
  Is the fuel pressure within specifications?
  
  Yes
  - Go To 5
  No
  - Perform the Checking The Fuel Delivery System diagnostic procedure as directed.

CHECK FUEL DELIVERY SYSTEM FOR LEAK DOWN

Courtesy of CHRYSLER GROUP, LLC

WARNING:

The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting, or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.

Close the Fuel System Isolation Valve (1) and then wait five minutes before proceeding.

Read the Fuel Inlet (2) and Fuel Outlet (3) Pressure Gauges. The pressure should not drop more than 10 psi on either gauge.

Does the fuel pressure drop more than 10 psi?

Yes - On Fuel Inlet Gauge (1)

Replace the appropriate fuel pump module as indicated in the table below.

Vehicle	Check Valve Location
LC	Auxiliary fuel pump module (right-side of fuel tank)
LX	Auxiliary fuel pump module (right-side of fuel tank)
JC	Primary fuel pump module (left-side of fuel tank)
JS	Primary fuel pump module (left-side of fuel tank)
MK	Primary fuel pump module (left-side of fuel tank)
PM	Primary fuel pump module (left-side of fuel tank)

NOTE:

The check valve allows residual fuel pressure to remain in the line and not de-pressurize into the tank when the fuel pump is off.

Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

Yes - On Fuel Outlet Gauge (2)

Replace the leaking fuel injector(s).
Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

If directed here by another test, return to that test. Otherwise, test complete.