7. Diagnostic Result Is Normal Even Though Cruise Can't Be Set

TECHNICAL DESCRIPTION (COMMENT)
The cause is probably that the fail-safe function is cancelling auto-cruise control. In this case, the scan tool MB991502 can be used to check the trouble symptoms in each system by checking the diagnostic trouble codes. The scan tool can also be used to check if the circuits of each input switch are normal or not by checking the input switch codes.

TROUBLESHOOTING HINTS
- Malfunction of the auto-cruise control switch.
- Malfunction of the clock spring.
- Malfunction of the clutch pedal position switch .
- Malfunction of the park/neutral position switch .
- Malfunction of the auto-cruise control-ECU.
- Damaged connector and harness.

DIAGNOSIS
Required Special Tool:
MB991502: Scan Tool (MUT-II)

STEP 1. Can the auto-cruise control communicate with scan tool MB991502?

CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.

1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to "ON" position.
3. Can the auto-cruise control communicate with the scan tool?

If yes. go to Step 2.

If no, inspect each trouble symptom. (Refer to Inspection Procedure number 1)

STEP 2. Is any diagnostic trouble code output?
Is any diagnostic trouble code output?

If no, go to Step 4.

If diagnostic trouble code number 11, 12,14, 15,16 or 17 is output, go to Step 3.

STEP 3. Is any of diagnostic trouble code numbers, 11, 12, 14,15, 16 or 17 output?
Refer to the following if any of the above diagnostic trouble code is output.
(Code number 11)
(Code number 12)
(Code number 14)
(Code number 15)
(Code number 16)
(Code number 17)

Then check that the malfunction is eliminated.

STEP 4. Using scan tool MB991502, check data list.

CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.

1. Turn the ignition switch ON.
2. Check the following items in the data list.
Refer to Data List Reference Table.
a. Item 04: Auto-cruise control "CANCEL" switch.
b. Item 05: Stoplight switch.
c. Item 14: Clutch pedal position switch .
d. Item 14: Park/neutral position switch .

If the checks above do not meet the specifications, follow the Diagnostic Trouble Code Procedures and Symptom Procedures below.
a. Item 04: Refer to Diagnostic Trouble Code Procedure number 15.
b. Item 05: Refer to Symptom Procedure number 2.
c. Item 14: Refer to Symptom Procedure number 3.
d. Item 14: Refer to Symptom Procedure number 4.

If the checks above meet the specifications, replace the auto-cruise control-ECU. Then check the malfunction is eliminated.