Inspection Procedure F-2

Any of the sunroof switch positions is defective.

TECHNICAL DESCRIPTION (COMMENT)
The sunroof switch or the sunroof motor assembly may be defective.

TROUBLESHOOTING HINTS
- Malfunction of the sunroof switch
- Malfunction of the sunroof motor assembly
- Damaged harness wires or connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Test Harness Set
- MB991502. Scan Tool (MUT-II)
- MB991529: Diagnostic Trouble Code Check Harness

STEP 1. Check method of the input signal

Q: Which is to be used, the scan tool or the voltmeter to check the input signal?

Scan tool MB991502: Go to Step 2.
Voltmeter: Go to Step 3.

STEP 2. Check the input signal (using scan tool MB991502).
Check the input signals from the sunroof switch.

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




1. Connect scan tool MB991502 to the data link connector.
2. Check that the tone alarm of scan tool MB991502 sounds when the input signal enters.

Q: Does the tone alarm of scan tool MB991502 sound when the input signal enters?

YES: Replace the sunroof motor assembly. The sunroof should work normally in all of the switch positions.
NO: Check the sunroof switch input circuit. Refer to Inspection Procedure O-19.

STEP 3. Check the input signal (by using a voltmeter).
Check the input signals from the sunroof switch.




1. Use special tool MB991529 to connect a voltmeter between ground terminal 4 or 5 and ETACS-ECU terminal 9 of the data link connector.
2. Check that the voltmeter indicator deflects once when the input signal enters.

Q: Does the voltmeter indicator deflect?

YES: Replace the sunroof motor assembly. The sunroof should work normally in all of the switch positions.
NO: Check the sunroof switch input circuit. Refer to Inspection Procedure O-19.