Inspection Procedure 5: Communication Between the Scan Tool and the TPMS Is Not Possible

INSPECTION PROCEDURE 5: Communication between the Scan Tool and the TPMS is not Possible.

Data Link Connector Circuit:

CIRCUIT OPERATION
The diagnostic output is made from the TPMS receiver (terminal 1) to the diagnostic output terminal (terminal 7) of the data link connector.

TECHNICAL DESCRIPTION (COMMENT)
When communication with the scan tool is not possible, the cause is probably an open circuit in the diagnostic output circuit or an open circuit in the TPMS receiver power/ground circuit.

TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CASE:)
^ Damaged harness wire or connector
^ Malfunction of the TPMS receiver

DIAGNOSIS

Required Special Tools:
^ MB991958: Scan Tool (M.U.T.-III Sub Assembly)
^ MB991824: Vehicle Communication Interface (V.C.I.)
^ MB991827: M.U.T.-III USB Cable
^ MB991910: M.U.T.-III Main Harness A

STEP 1. Check the TPMS warning light.
Check whether the TPMS warning light illuminates for three seconds after the ignition switch is turned to the "ON" position.
Q: Does the TPMS warning light illuminate for three seconds?
YES: Check that the TPMS warning light illuminates for three seconds and then goes out. Then go to Step 2.
NO: Go to TPMS Inspection Procedure No.3 "The TPMS Warning Light does not Illuminate as a Bulb Check for Three Seconds when the Ignition Switch is Turned to the "ON" Position".

STEP 2. Check the following connectors.





^ Joint connector C-03





^ Data link connector C-125





^ TPMS receiver connector C-133
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 3.
NO: Repair it. Then go to Step 4.

STEP 3. Check the following harness wire.








^ The wire between data link connector (terminal 7) and TPMS receiver connector C-133 (terminal 1)
Q: Is the harness wire damaged?
YES: Repair or replace it. Then go to Step 4.
NO: Replace the TPMS receiver and execute "Tire Pressure Sensor ID Registration" on scan tool MB991958 "Special Function". Then go to Step 4.

STEP 4. Retest the system.

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.





1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Retest the system.
Q: Does the scan tool communicate with the TPMS system?
YES: The procedure is complete.
NO: Repeat this procedure from Step 1.