Inspection Procedure 6

Inspection Procedure 6: Hunting (Repeated Acceleration and Deceleration) Occurs at the Set Vehicle Speed [M/T].

COMMENT

The vehicle speed sensor or the throttle body is suspected.

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

- Malfunction of the vehicle speed sensor.
- Malfunction of the throttle body.
- Malfunction of the MFI system.
- Malfunction of the ECM.

DIAGNOSTIC PROCEDURE

STEP 1. Using scan tool MB991958, check for MFI system 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.

Connect scan tool MB991958 to the data link connector (Refer to Reading and Clearing Diagnostic Trouble Codes).

(2)Turn the ignition switch to the "ON" position.

(3)Set scan tool MB991958 to check for MFI system DTC Reading and Clearing Diagnostic Trouble Codes).

Q. Is any DTC set?

YES Repair the MFI system Multiport Fuel Injection (MFI)). Then go to Step 4.
NO Go to Step 2.
STEP 2. Using scan tool MB991958, check data list item 04: Vehicle speed.

(1)Connect scan tool MB991958 to the data link connector (Refer to Reading and Clearing Diagnostic Trouble Codes).

(2)Turn the ignition switch to the "ON" position.

(3)Set scan tool MB991958 to data reading mode for cruise control system (Refer to Scan Tool Testing and Procedures.)

- Item 04: Vehicle speed.

Q. Is the check result satisfactory?

YES Go to Step 3.
NO Replace the ECM [ Removal and Replacement]. Then go to Step 4.
STEP 3. Check the symptom.

Q. Does hunting occur?

YES Replace the ECM [ Removal and Replacement.] Then go to Step 4.
NO It can be assumed that this malfunction is intermittent How to Cope With Intermittent Malfunctions.)
STEP 4. Check the symptom.

Q. Does hunting occur?

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