Diagnostic Procedure
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
- MB991223: Harness Set
- MB992006: Extra Fine Probe
- STEP 1. Using scan tool MB991958, diagnose the CAN bus line. 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.
- Connect scan tool MB991958 to the data link connector (Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-III). .
- Turn the ignition switch to the "ON" position.
- Set scan tool MB991958 to diagnose the CAN bus line (Refer to HOW TO DIAGNOSE THE CAN BUS LINE
.
Q: Is the check result satisfactory?
- YES: Go to Step 2.
- NO: Repair the CAN bus lines (Refer to CAN BUS DIAGNOSTICS CHART . Then go to Step 12.
- STEP 2. Using scan tool MB991958, check the data list item 74: Brake light switch.
- Connect scan tool MB991958 to the data link connector (Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-III). .
- Turn the ignition switch to the "ON" position.
- Set scan tool MB991958 to data reading mode for cruise control system (Refer to CRUISE CONTROL SYSTEM DIAGNOSTIC TROUBLE CODES
.
- Item 74: Brake light switch.
- When the brake pedal is depressed, the display on scan tool MB991958 should be "ON".
- When the brake pedal is released, the display on scan tool MB991958 should be "OFF".
Q: Is the switch operating properly?
- YES: Go to Step 6.
- NO: Go to Step 3.
- Item 74: Brake light switch.
- STEP 3. Check the stoplight operation.
Check the stoplight operation.
OK:
Brake pedal depressed: Stoplight will illuminate
Brake pedal not depressed: Stoplight does not illuminate
Q: Is the stoplight operating properly?
- YES: Go to Step 4.
- NO: Check the stoplight system (Refer to INSPECTION PROCEDURE 3 . Then go to Step 12.
- STEP 4. Using scan tool MB991958, check the ETACS system data list item 290: Brake light switch.
- Connect scan tool MB991958 to the data link connector (Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-III). .
- Turn the ignition switch to the "ON" position.
- Set scan tool MB991958 to data reading mode for ETACS system (Refer to
DATA LIST REFERENCE TABLE
.
- Item 290: Brake light switch.
- When the brake pedal is depressed, the display on scan tool MB991958 should be "ON".
- When the brake pedal is released, the display on scan tool MB991958 should be "OFF".
Q: Is the switch operating properly?
- YES: Go to Step 5.
- NO: Replace the ETACS-ECU (Refer to REMOVAL AND INSTALLATION . Then go to Step 12.
- Item 290: Brake light switch.
- STEP 5. Using scan tool MB991958, check the data list item 74: Brake light switch.
- Connect scan tool MB991958 to the data link connector (Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-III). .
- Turn the ignition switch to the "ON" position.
- Set scan tool MB991958 to data reading mode for cruise control system (Refer to CRUISE CONTROL SYSTEM DIAGNOSTIC TROUBLE CODES
.
- Item 74: Brake light switch.
- When the brake pedal is depressed, the display on scan tool MB991958 should be "ON".
- When the brake pedal is released, the display on scan tool MB991958 should be "OFF".
Q: Is the switch operating properly?
- YES: Go to Step 6.
- YES: Replace the ECM [Refer to ENGINE CONTROL MODULE (ECM) ] < 2.4L Engine > or [Refer to ENGINE CONTROL MODULE (ECM) ] < 3.0L Engine >. Then go to Step 12.
- Item 74: Brake light switch.
- STEP 6. Using scan tool MB991958, check the data list item 89: Normally closed brake switch.
- Connect scan tool MB991958 to the data link connector (Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-III). .
- Turn the ignition switch to the "ON" position.
- Set scan tool MB991958 to data reading mode for cruise control system (Refer to CRUISE CONTROL SYSTEM DIAGNOSTIC TROUBLE CODES
.
- Item 89: Normally closed brake switch.
- When the brake pedal is depressed, the display on scan tool MB991958 should be "ON".
- When the brake pedal is released, the display on scan tool MB991958 should be "OFF".
Q: Is the switch operating properly?
- YES: Go to Step 11.
- NO: Go to Step 7.
- Item 89: Normally closed brake switch.
- STEP 7. Check ECM connector B-11 and stoplight switch connector C-124 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Refer to HARNESS CONNECTOR INSPECTION .
Q: Are the connectors and terminals in good condition?
- YES: Go to Step 8.
- NO: Repair or replace the damaged connector. Then go to Step 12.
- STEP 8. Check the harness wire between ECM connector B-11 terminal number 108 and stoplight switch connector C-124 terminal number 3, and between stoplight switch connector C-124 terminal number 4 and body ground, for damage.
Check harness wire for open/short circuit and damage.
Q: Are the harness wires in good condition?
- YES: Go to Step 9.
- NO: Repair or replace the damaged harness wire. Then go to Step 12.
- STEP 9. Check the stoplight switch.
Refer to STOPLIGHT SWITCH CHECK .
Q: Is the stoplight switch operating properly?
- YES: Go to Step 10.
- NO: Replace the stoplight switch (Refer to BRAKE PEDAL . Then go to Step 12.
- STEP 10. Using scan tool MB991958, check the data list item 89: Normally closed brake switch.
- Connect scan tool MB991958 to the data link connector (Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-III). .
- Turn the ignition switch to the "ON" position.
- Set scan tool MB991958 to data reading mode for cruise control system (Refer to CRUISE CONTROL SYSTEM DIAGNOSTIC TROUBLE CODES
.
- Item 89: Normally closed brake switch.
- When the brake pedal is depressed, the display on scan tool MB991958 should be "ON".
- When the brake pedal is released, the display on scan tool MB991958 should be "OFF".
Q: Is the switch operating properly?
- YES: Go to Step 11.
- NO: Replace the ECM [Refer to ENGINE CONTROL MODULE (ECM) ] < 2.4L Engine > or [Refer to ENGINE CONTROL MODULE (ECM) ] < 3.0L Engine >. Then go to Step 12.
- Item 89: Normally closed brake switch.
- STEP 11. Read the cruise control system DTC.
- Disconnect the negative (-) battery terminal, to erase the DTC of the cruise control system.
- Connect the negative (-) battery terminal.
- Turn the ignition switch to the "ON" position, and press the "ON/OFF" switch to turn the cruise control system to ON (turn on the "CRUISE" indicator light.)
- With the cruise control switches not operated, depress the brake pedal for several seconds, and then read the DTC of the cruise control system (Refer to CRUISE CONTROL SYSTEM DIAGNOSTIC TROUBLE CODES
.
Q: Is DTC 22 set?
- YES: Replace the ECM [Refer to ENGINE CONTROL MODULE (ECM) ] < 2.4L Engine > or [Refer to ENGINE CONTROL MODULE (ECM) ] < 3.0L Engine >. Then go to Step 12.
- NO: It can be assumed that this malfunction is intermittent (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION .
- STEP 12. Using scan tool MB991958, check the data list item 74: Brake light switch, item 89: Normally closed brake switch.
- Connect scan tool MB991958 to the data link connector (Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-III). .
- Turn the ignition switch to the "ON" position.
- Set scan tool MB991958 to data reading mode for cruise control system (Refer to CRUISE CONTROL SYSTEM DIAGNOSTIC TROUBLE CODES
.
- Item 74: Brake light switch.
- When the brake pedal is depressed, the display on scan tool MB991958 should be "ON."
- When the brake pedal is released, the display on scan tool MB991958 should be "OFF."
- Item 89: Normally closed brake switch.
- When the brake pedal is depressed, the display on scan tool MB991958 should be "ON."
- When the brake pedal is released, the display on scan tool MB991958 should be "OFF."
Q: Is the switch operating properly?
- YES: Go to Step 13.
- NO: Return to Step 2.
- Item 74: Brake light switch.
- STEP 13. Read the cruise control system DTC.
- Disconnect the negative (-) battery terminal, to erase the DTC of the cruise control system.
- Connect the negative (-) battery terminal.
- Turn the ignition switch to the "ON" position, and press the "ON/OFF" switch to turn the cruise control system to ON (turn on the "CRUISE" indicator light.)
- With the cruise control switches not operated, depress the brake pedal for several seconds, and then read the DTC of the cruise control system (Refer to CRUISE CONTROL SYSTEM DIAGNOSTIC TROUBLE CODES
.
Q: Is DTC P22 set?
- YES: Return to Step 1.
- NO: The procedure is complete.