INSPECTION PROCEDURE O-1: The ignition switch (ACC) signal is not sent to the ETACS-ECU.: Diagnosis

Required Special Tools: 

• MB991223: Test Harness Set
• MB991502: Scan Tool (MUT-II)
• MB991529: Diagnostic Trouble Code Check Harness

1. STEP 1. Check the ignition switch (ACC) circuit to the ETACS-ECU. Test at ETACS-ECU connector C-319. 
   1. Disconnect the ETACS-ECU connector C-319 and measure the voltage available at the junction block side of the connector.
   2. Turn the ignition switch to the "ACC" position.
      Fig 1: Identifying Connector C-319 - Junction Block Side

      Courtesy of DAIMLERCHRYSLER CORPORATION
   3. Measure the voltage between terminal 4 and ground.
      • The voltage should equal approximately 12 volts (battery positive voltage).

   Q: Is the measured voltage approximately 12 volts (battery positive voltage)? 

   YES  : Replace the ETACS-ECU. The ignition switch (ACC) input signal should be able to be checked and the devices or functions, which are described in the "TECHNICAL DESCRIPTION (COMMENT) ," should work normally.

   NO:  Go to Step 2.

   Fig 2: Measuring Voltage Between Terminal 4 And Ground

   Courtesy of DAIMLERCHRYSLER CORPORATION
2. STEP 2. Check the ETACS-ECU connector C-319 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Is ETACS-ECU connector C-319 in good condition? 

   YES  : Go to Step 3.

   NO:  Repair or replace the damaged component(s). Refer to , HARNESS CONNECTOR INSPECTION . The ignition switch (ACC) input signal should be able to be checked and the devices or functions, which are described in the "TECHNICAL DESCRIPTION (COMMENT) ," should work normally.

   Fig 3: Identifying Connector C-319 - Junction Block Side

   Courtesy of DAIMLERCHRYSLER CORPORATION
3. STEP 3. Check the wiring harness between ETACS-ECU connector C-319 (terminal 4) and ignition switch (ACC). 
   Fig 4: Identifying Connector C-319 - Junction Block Side

   Courtesy of DAIMLERCHRYSLER CORPORATION
   NOTE: Also check junction block connector C-312 and intermediated connector C-209 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If junction block connector C-312 or intermediated connector C-209 is damaged, repair or replace the damaged component(s) as described in , HARNESS CONNECTOR INSPECTION .

   Q: Are the wiring harness between ETACS-ECU connector C-319 (terminal 4) and ignition switch (ACC) in good condition? 

   YES  : No action is necessary and testing is complete.

   NO:  The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. The ignition switch (ACC) input signal should be able to be checked and the devices or functions, which are described in the "TECHNICAL DESCRIPTION (COMMENT) ," should work normally.

   Fig 5: Identifying Connector C-312 - Harness Side

   Courtesy of DAIMLERCHRYSLER CORPORATION
   Fig 6: Identifying Connector C-209

   Courtesy of DAIMLERCHRYSLER CORPORATION