Inspection Procedure 1

Inspection Procedure 1: Throttle Valve will not Fully Open or Close

COMMENT

The throttle body or accelerator pedal position sensor is suspected.

TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CASE:)

- Malfunction of the throttle body.
- Malfunction of the accelerator pedal position sensor.
- Malfunction of the engine control module (ECM).

DIAGNOSIS

Required Special Tools:

- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (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 (DTC).





(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 DTC. 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 any DTC set?

YES Repair MFI system. Multiport Fuel Injection (MFI)). Then go to Step 2.

NO Go to Step 2.

STEP 2. Retest the system.

Q. Does the throttle valve fully open and close?

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