Inspection Procedure 6

INSPECTION PROCEDURE 6: Hunting (Repeated Acceleration and Deceleration) Occurs at the Set Vehicle Speed.

COMMENT
The output shaft speed sensor signal or the throttle body is suspected.

TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CASE:)
- Malfunction of the vehicle speed sensor (M/T).
- Malfunction of the output shaft speed sensor (A/T).
- Malfunction of the throttle body.
- Malfunction of the ECM (M/T) or PCM (A/T).

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 (M/T).







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. Connect scan tool MB991958 to the data link connector. Scan Tool Connecting
2. Turn the ignition switch to the "ON" position.
3. Check for MFI system diagnostic trouble code. (Refer to, MFI Diagnosis - Diagnostic Function - How to Read and Erase Diagnostic Trouble Code) [2.4L engine] With Manufacturer's Scan Tool or (Refer to, MFI Diagnosis - Diagnostic Function - How to Read and Erase Diagnostic Trouble Code) [3.8L engine]. With Manufacturer's Scan Tool
4. Turn the ignition switch to the "LOCK" (OFF) position.
5. Disconnect scan tool MB991958.

Q: Is DTC P0500 set?

YES : Refer to, MFI Diagnosis - Diagnostic Trouble Code Procedures - DTC P0500: Vehicle Speed Sensor Malfunction (M/T) [2.4L engine] P0500or Refer to, MFI Diagnosis - Diagnostic Trouble Code Procedures - DTC P0500: Vehicle Speed Sensor Malfunction (M/T) [3.8L engine]. P0500 Then go to Step 5.

NO : Go to Step 2.

STEP 2. Using scan tool MB991958, read the A/T system diagnostic trouble code (A/T).







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. Connect scan tool MB991958 to the data link connector. Scan Tool Connecting
2. Turn the ignition switch to the "ON" position.
3. Check for A/T system diagnostic trouble code. (Refer to, A/T Diagnosis - Diagnostic Function - How to Read and Erase Diagnostic Trouble Code). Reading and Clearing Diagnostic Trouble Codes
4. Turn the ignition switch to the "LOCK" (OFF) position.
5. Disconnect scan tool MB991958.

Q: Is DTC P1767 set?

YES : Refer to, A/T Diagnosis - Diagnostic Trouble Code Procedures - DTC P1767: Output Shaft Speed Sensor System. Then go to Step 5.

NO : Go to Step 3.

STEP 3. Using scan tool MB991958, read the MFI system diagnostic trouble code.







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. Connect scan tool MB991958 to the data link connector. Scan Tool Connecting
2. Turn the ignition switch to the "ON" position.
3. Check for MFI system diagnostic trouble code (Refer to, MFI Diagnosis - Diagnostic Function - How to Read and Erase Diagnostic Trouble Code) [2.4L engine] With Manufacturer's Scan Tool or (Refer to, MFI Diagnosis - Diagnostic Function - How to Read and Erase Diagnostic Trouble Code) [3.8L engine]. With Manufacturer's Scan Tool
4. Turn the ignition switch to the "LOCK" (OFF) position.
5. Disconnect scan tool MB991958.

Q: Is any DTC set?

YES : Diagnose the MFI system. (Refer to, MFI Diagnosis - Diagnostic Trouble Code Chart) [2.4L engine] Diagnostic Trouble Code Descriptions or (Refer to, MFI Diagnosis - Diagnostic Trouble Code Chart) [3.8L engine]. Diagnostic Trouble Code Descriptions Then go to Step 5.

NO : Go to Step 4.

STEP 4. Retest the system

Q: Does hunting occur?

YES : Replace the ECM (M/T) or PCM (A/T). Then go to Step 5.

NO : It can be assumed that this malfunction is intermittent.

STEP 5. Retest the system

Q: Does hunting occur?

YES : Return to Step 1.

NO : The procedure is complete.