Inspection Procedure F-3

Power window relay: Power window timer function does not work normally.

TECHNICAL DESCRIPTION (COMMENT)
The sunroof motor assembly deactivates the sunroof timer if the SWS communication line is open circuited. In addition, when the doors are opened if the door switch circuit is defective and the timer is on, the sunroof timer should not operate normally.

TROUBLESHOOTING HINTS
- Malfunction of the driver's or passenger's door 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 (by using scan tool MB991502).
Check the in put signals from the following switches:
- Ignition switch (IG1)
- Driver's and passenger's door switch
- Sunroof switch

NOTE: It can be determined whether the harness wires between the sunroof motor assembly and the ETACS-ECU is defective or not by checking the SWS communication line.

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 timer function should work normally.
NO: Check the relevant input circuit.

STEP 3. Check the input signal (by using a voltmeter).
Check the input signals from the following switches:
- Ignition switch (IG1)
- Driver's and front passengers door 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 timer function should work normally.
NO: Check the relevant input circuit.