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:)

- Fuel injector failed.
- Open or shorted fuel injector circuit, or loose connector.
- Bent, twisted or clogged fuel main pipe or fuel high-pressure hose.
- Malfunction of the fuel tank pump and gauge assembly.

DIAGNOSIS

Required Special Tools:

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

STEP 1. Using scan tool MB991958, read the MFI system diagnostic trouble code.





(1)
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.

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).
(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 Repair MFI system Multiport Fuel Injection (MFI)). Then go to Step 6.

NO Go to Step 2.

STEP 2. Check the fuel pressure.

Release residual pressure from the fuel line to prevent fuel spray Testing and Inspection).

Q. Is the fuel pressure in good condition?

YES Go to Step 5.
NO Go to Step 3.
STEP 3. Check for bending, twisting or clogging of the fuel main pipe and fuel high-pressure hose.





Q. Are the fuel main pipe and fuel high-pressure hose in good condition?

YES Go to Step 4.

NO Repair or replace the fuel main pipe or fuel high-pressure hose. Then go to Step 6
.

STEP 4. Check the fuel pump operation.

Testing and Inspection.

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

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

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.