Symptom Related Diagnostic Procedures

SYMPTOM PROCEDURES

INSPECTION PROCEDURE 1 : Engine Malfunctions Due to Insufficient Fuel Supply

TROUBLESHOOTING HINTS (The most likely causes for this case: )

- Injector failed.
- Open or shorted injector circuit, or loose connector.
- Bent, twisted or clogged fuel pipe or hose.
- Malfunction of the fuel pump module.

DIAGNOSIS

Required Special Tools:

- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A

STEP 1. Using scan tool MB991958, read the diagnostic trouble code (DTC).





CAUTION:
To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

(1)Ensure that the ignition switch is at the "LOCK" (OFF) position.
(2)Start up the personal computer.
(3)Connect special tool MB991827 to special tool MB991824 and the personal computer.
(4)Connect special tool MB991910 to special tool MB991824.
(5)Connect special tool MB991910 to the data link connector.
(6)Turn the power switch of special tool MB991824 to the "ON" position.
NOTE:
When special tool MB991824 is energized, special tool MB991824 indicator light will be illuminated in a green color.

(7)Start the M.U.T.-III system on the personal computer.
(8)Turn the ignition switch to the "ON" position.
(9)Check for MFI system diagnostic trouble code Reading and Clearing Diagnostic Trouble Codes, refer to Diagnostic Function, How to Read and Erase Diagnostic Trouble Codes [3.8L Engine] Monitors, Trips, Drive Cycles and Readiness Codes).
(10)Turn the ignition switch to the "LOCK" (OFF) position, and then remove scan tool MB991958 in the reverse order of installation.

Q. Is the DTC set?

YES Refer to Diagnostic Trouble Code Chart [2.4L Engine] Multiport Fuel Injection (MFI) , [3.8L Engine] Multiport Fuel Injection (MFI).

NO Turn the ignition switch to the "LOCK" (OFF) position, and then remove scan tool MB991958 in the reverse order of installation. Go to Step 2.

STEP 2. Check the fuel pressure.

Release residual pressure from the fuel line to prevent fuel spray. Refer to Fuel Pressure Test. [2.4L Engine] Testing and Inspection ,[3.8L Engine] Testing and Inspection.

Q. Is the fuel pressure in good condition?

YES Go to Step 5.
NO Repair or replace. Then go to Step 3.
STEP 3. Check for bending, twisting or clogging of the fuel pipe or hose.





Q. Are the fuel pipe and hose in good condition?

YES Go to Step 4.

NO Repair or replace. Then go to Step 6.

STEP 4. Check the fuel pump module operation.

Refer to Fuel Pump Operation Check. [2.4L Engine] Testing and Inspection ,[3.8L Engine] Testing and Inspection .

Q. Is the fuel pump module operation in good condition?

YES Then go to Step 5.
NO Replace (Refer to Removal and Replacement). Then go to Step 6.
STEP 5. Check the inside of the fuel tank for contamination and rust.

(1)Drain fuel.

(2)Remove the fuel tank (Refer to Removal and Replacement).

Q. Is the fuel tank in good condition?

YES Go to Step 6.
NO Replace the fuel filter, and clean the fuel tank and fuel line. Then go to Step 6.
STEP 6. Retest the system.

Q. Is the engine malfunction eliminated?

YES The procedure is complete.
NO Return to Step 1.