Inspection Procedure 5

INSPECTION PROCEDURE 5: In the Inspection with the Scan Tool Service Data, the Parking Brake Switch is not Turned ON or Turned OFF.









CIRCUIT OPERATION
The ABS-ECU monitors the parking brake switch to optimize the ABS control.

TECHNICAL DESCRIPTION (COMMENT)
The cause may be an open or a short circuit between the parking brake switch and the ABS-ECU.

TROUBLESHOOTING HINTS
The most likely causes for this case are:
^ Damaged wiring harness or connector
^ Malfunction of the parking brake switch
^ Malfunction of the brake modulator hydraulic unit (integrated with ABS-ECU)

DIAGNOSIS
Required Special Tools:
^ MB991223: Harness Set
^ MB991958: Scan Tool (MUT-III Sub Assembly)
^ MB991824: Vehicle Communication Interface (V.C.I.)
^ MB991827: MUT-III USB Cable
^ MB991911: MUT-III Main Harness B

STEP 1. Using scan tool MB991958, check data list.

CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the LOOK (OFF) position before connecting or disconnecting scan MB991958.





1. Connect scan tool MB991958 as shown in the illustration.
2. Start the engine.
3. Set scan tool MB991958 to data reading mode for following item.
^ Item 29: Parking brake switch





4. Confirm the indicated ON/OFF state as follows:
Q: Is the parking brake switch input normal?
YES: This malfunction is intermittent. Refer to How to Use Troubleshooting/Inspection Service Points - How to Cope With Intermittent Malfunction.
NO: Go to Step 2.

STEP 2. Check the parking brake switch circuit at ABS-ECU connector B-118.





1. Disconnect ABS-ECU connector B-118 and measure at the harness side.
2. Check for continuity between terminal 1 and ground with pulling or releasing the parking brake lever. If the parking brake lever is pulled, there should be no continuity, and if the parking brake lever is released, there should be continuity (less than 2 ohms).
Q: Does continuity exist when the parking brake lever is released, and dose continuity not exist when the parking brake lever is pulled?
YES: Go to Step 3.
NO: Go to Step 4.

STEP 3. Check the following connector.





ABS-ECU connector B-118
Check the connector for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Are the connector and terminals in good condition?
YES: Replace the brake modulator hydraulic unit (integrated with ABS-ECU). Then go to Step 6.
NO: Go to Step 6.

STEP 4. Check the following connectors.





^ ABS-ECU connector B-118





^ Intermediate connector C-124
^ Joint connector C-23





^ Parking brake switch connector D-28
Check the connectors for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Are the connectors and terminals in good condition?
YES: Go to Step 5.
NO: Repair it and then go to Step 6.

STEP 5. Check the following harness wire.








The wire between parking brake switch connector D-28 (terminal 1) and ABS-ECU connector B-118 (terminal 1)
Q: Is the harness wire damaged?
YES: Repair or replace it and then go to Step 6.
NO: Replace the parking brake switch. Then go to Step 6.

STEP 6. Recheck for diagnostic trouble code.
Q: Does the parking brake switch turn ON/OFF normally in the inspection by scan tool service data?
YES: The procedure is complete.
NO: Return to Step 1.