DTC P0148 [MZI-3.7]

id0102d2880600

DTC P0148

Fuel delivery error
DETECTION CONDITION
•  At least 1 bank is lean at wide open throttle (WOT).
POSSIBLE CAUSE
•  Damage or leakage fuel delivery system
•  Vacuum leaks
•  Fuel pump or related wiring harness electrical malfunction
•  Damaged or worn fuel pump
•  Improper operated fuel injector
•  Severely restricted fuel filter
•  Severely restricted fuel supply line
•  PCM malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION
1
VERIFY FREEZE FRAME DATA HAS BEEN RECORDED
•  Has FREEZE FRAME DATA been recorded?
Yes
Go to the next step.
No
Record FREEZE FRAME DATA on the repair order, then go to the next step.
2
VERIFY RELATED SERVICE INFORMATION AVAILABILITY
•  Verify related Service Information availability.
•  Is any related Service Information available?
Yes
Perform repair or diagnosis according to the available Service Information.
•  If the vehicle is not repaired, go to the next step.
No
Go to the next step.
3
INSPECT SYSTEM INTEGRITY
•  Visually inspect the complete fuel delivery system for damage and leakage.
•  Check the following:
―  Fuel lines and connections
―  Relays
―  Fuel tank
―  Fuel pump
―  Fuel pressure regulator
―  Fuel pulse damper
―  Fuel rail at fuel injectors
―  Damaged connector pins
―  Electrical connectors not fully engaged
•  Verify that the vehicle has followed the maintenance schedule.
•  Verify that the fuse integrity.
•  Verify that the battery is fully charged.
•  Verify that there is clean sufficient fuel.
•  Is a concern present?
Yes
Repair if necessary. Then go to Step 11.
No
Go to the next step.
4
INSPECT ALL SYSTEM RELATED DEVICES (SENSOR, DAMPER OR REGULATOR) FOR LEAKAGE
•  Turn the ignition switch off.
•  Connect the fuel pump connector.
•  Turn the ignition switch to the ON position (Engine running)
•  Check for manifold vacuum at each system related component with a vacuum line.
•  Turn the ignition switch off.
•  Wait 10 s.
•  Turn the ignition switch to the ON position (Engine running)
•  Run the engine for approx. 10 s.
•  Turn the ignition switch off.
•  Remove the vacuum hose on each system device connected to the fuel rail.
•  Inspect for the presence of fuel in the vacuum line of each device connected to the fuel rail.
•  Are all vacuum lines for system related devices indicating no fuel present?
Yes
Go to the next step.
No
If the vacuum line connected to a component indicates that a fuel leak is present, install a new component. Then go to Step 11.
5
INSPECT FUEL PRESSURE
•  Turn the ignition switch off.
•  Relieve the fuel pressure. Refer to the Workshop Manual Fuel System Pressure Release procedure.
•  Connect the mechanical fuel pressure gauge.
•  Turn the ignition switch to the ON position (Engine off)
•  Pressurize the fuel system. Refer to the Workshop Fuel System for the Fuel System Pressure Release procedure to pressurize the fuel system.
•  Compare the fuel pressure reading to the Fuel System Specification Chart.
•  Is the fuel pressure within range?
Yes
Go to Step 9.
No
Go to the next step.
6
INSPECT FUEL PUMP GROUND CIRCUIT FOR OPEN CIRCUIT IN WIRING HARNESS
Note
•  Refer to the Wiring Diagrams Manual for schematic and connector information.
•  Disconnect the fuel pump connector.
•  Measure the voltage between fuel pump connector terminal D (wiring harness-side) and battery positive terminal.
•  Is the voltage more than 10 V?
Yes
Go to the next step.
No
Repair or replace suspected part, then go to Step 11.
7
INSPECT FUEL PUMP POWER SUPPLY CIRCUIT FOR OPEN CIRCUIT IN WIRING HARNESS
•  Disconnect the fuel pump connector.
•  Turn the ignition switch to the ON position (Engine off)
•  Access the PCM and control the FP PID.
•  Measure the voltage between fuel pump connector terminal B (wiring harness-side) and body ground.
•  Is the voltage more than 10 V?
Yes
Go to the next step.
No
Repair or replace suspected part, then go to Step 11.
8
INSPECT FUEL PRESSURE LEAK
Note
•  When the fuel pump is commanded off, the fuel pressure may substantially decrease and then stabilize.
Note
•  During output state control, the fuel pump stays commanded on for only approx. 5 s.
•  Connect the mechanical fuel pressure gauge.
•  Turn the ignition switch to the ON position (Engine off)
•  Access the PCM and control the FP PID.
•  Run the fuel pump to obtain maximum fuel pressure.
•  Command the fuel pump off.
•  Allow the fuel pressure to stabilize.
•  Record the stabilized reading.
•  Monitor the fuel pressure for 1 min.
•  Does the fuel pressure remain within 34 kPa {0.35 kgf/cm2, 4.93 psi} of the recorded reading after 1 min?
Yes
Perform the KOEO self-test. Go to Step 10.
No
Go to the next step.
9
INSPECT FUEL INJECTOR OPERATION
•  Remove the fuel injector.
•  Inspect the fuel injector operation.
•  Is the fuel injector normal?
Yes
Go to the next step.
No
Replace the fuel injector, then go to Step 11.
10
INSPECT FUEL SUPPLY LINE FOR RESTRICTION
Note
•  Observe the Warnings, Cautions, and Notes.
•  Disconnect the fuel supply line at the fuel rail.
•  Disconnect the fuel supply line at the fuel pump.
•  Check the fuel supply line for restriction.
•  Apply 21—34 kPa {2142—3467 mmHg, 84.34—136.4 inHg} air pressure to the fuel supply line.
•  Does air flow freely through the line?
Yes
Replace the fuel pump module. Then go to the next step.
No
Repair the cause of the restriction. Then go to the next step.
11
VERIFY TROUBLESHOOTING OF DTC P0148 HAS BEEN COMPLETED
•  Verify that all disconnected connectors are reconnected.
•  Turn the ignition switch to the ON position (Engine off).
•  Clear the DTC from the PCM memory using the M-MDS.
•  Start the engine and run it at idle.
•  Retrieve DTCs using the M-MDS.
•  Is the PENDING CODE for this DTC present?
Yes
Replace PCM, then go to the next step.
(See PCM REMOVAL/INSTALLATION [MZI-3.7].)
No
Go to the next step.
12
VERIFY AFTER REPAIR PROCEDURE
•  Perform “AFTER REPAIR PROCEDURE”.
•  Are any DTC present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [MZI-3.7].)
No
Troubleshooting completed.