Inspection Procedure 3: the TPMS Warning Light Does Not Illuminate As A Bulb Check For Three Seconds When the Ignition Switch I

INSPECTION PROCEDURE 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.

Connectors: C-01, C-04, C-24, C-202, C-215, C-121:

CIRCUIT OPERATION
For three seconds after the ignition switch is turned to the "ON" position, the TPMS receiver illuminates the TPMS warning light to check any breaks in the TPMS warning light circuit.

TECHNICAL DESCRIPTION (COMMENT)
If the TPMS warning light does not illuminate for three seconds when the ignition switch is turned to the "ON" position, diagnose the TPMS warning light signal circuit, power supply to the TPMS receiver, ignition signal, and/or ground circuit.

TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CASE:)
- TPMS warning light signal harness wire open circuit
- Ignition signal harness wire of the TPMS receiver or battery power supply harness wire open circuit
- Ground harness wire of the TPMS receiver open circuit
- Malfunction of the combination meter
- Malfunction of the TPMS receiver

DIAGNOSIS
Required Special Tool:
- MB991223: Harness Set
- MB992006: Extra Fine Probe

STEP 1. Measure the voltage at C-121 TPMS receiver connector.

Connector: C-121:

(1) Disconnect TPMS receiver connector C-121, and check at the harness connector (component side).

Connector: C-121:

(2) Measure the voltage between terminal 5 and ground. It should measure battery positive voltage (approximately 12 volts).
(3) Turn the ignition switch to the "ON" position.

Connector: C-121:

(4) Measure the voltage between terminal 10 and ground. It should measure battery positive voltage (approximately 12 volts).
Q:Is battery positive voltage (approximately 12 volts) present?
YES [all the measured voltages are equivalent to battery positive voltage]: Go to Step 6.
NO [voltage between terminal 5 and ground is not battery positive voltage]: Go to Step 2.
NO [voltage between terminal 10 and ground is not battery positive voltage]: Go to Step 4.

STEP 2. Check TPMS receiver connector C-121 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Pinout Values and Diagnostic Parameters

Connector: C-121:

Q:Is the TPMS receiver connector C-121 in good condition?
YES: Go to Step 3.
NO: Repair it. Then go to Step 12.

STEP 3. Check the wiring harness between TPMS receiver connector C-121 (terminal 5) and the battery.

Connector: C-121:

Connector: C-24:

NOTE: Also check intermediate connector C-24 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-24 is damaged, repair or replace the connector as described in Harness Connector Inspection.

Q:Is the wiring harness between TPMS receiver connector C-121 (terminal 5) and the battery in good condition?
YES: Repair or replace it. Then go to Step 12.
NO: Repeat the troubleshooting from Step 1.

STEP 4. Check TPMS receiver connector C-121 and junction block connector C-215 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Pinout Values and Diagnostic Parameters

Connector: C-121:

Connector: C-215:

Q:Are TPMS receiver connector C-121 and junction block connector C-215 in good condition?
YES: Go to Step 5.
NO: Repair it. Then go to Step 12.

STEP 5. Check the wiring harness between TPMS receiver connector C-121 (terminal 10) and junction block connector C-215 (terminal 25).

Connector: C-121:

Connector: C-215:

Q:Is the wiring harness between TPMS receiver connector C-121 (terminal 10) and junction block connector C-215 (terminal 25) in good condition?
YES: Repair or replace it. Then go to Step 12.
NO: Repeat the troubleshooting from Step 1.

STEP 6. Check the wiring harness for open circuit.

Connector: C-121:

(1) Disconnect TPMS receiver connector C-121, and measure the resistance at the harness side.

Connector: C-121:

(2) Measure the resistance between terminal 6 and ground.
OK: Less than 2 ohms
Q:Is the check result normal?
YES: Go to Step 9.
NO: Go to Step 7.

STEP 7. Check TPMS receiver connector C-121 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Connector: C-121:

Q:Is TPMS receiver connector C-121 in good condition?
YES: Go to Step 8.
NO: Repair it. Then go to Step 12.

STEP 8. Check the wiring harness between TPMS receiver connector C-121(terminal 6) and ground.

Connector: C-121:

Q:Is the wiring harness between TPMS receiver connector C-121(terminal 6) and ground in good condition?
YES: Repair or replace it. Then go to Step 12.
NO: Return to Step 6.

STEP 9. Check the TPMS warning light circuit at TPMS receiver connector C-121.

Connector: C-121:

(1) Disconnect TPMS receiver connector C-121.
(2) Turn the ignition switch to the "ON" position.

Connector: C-121:

(3) Terminal 10 of disconnected connector C-121 from the TPMS receiver. The TPMS warning light should illuminate.
Q:Does the TPMS warning light illuminate?
YES: Replace the TPMS receiver and execute "Tire Pressure Sensor ID Registration" on scan tool M B991958 "Special Function". Then go to Step 12.
NO: Go to Step 10.

STEP 10. Check TPMS receiver connector C-121 and combination meter connector C-04 for loose, corroded or damage terminals, or terminals pushed back in the connector. Pinout Values and Diagnostic Parameters

Connector: C-04:

Connector: C-121:

Q:Are TPMS receiver connector C-121 and combination meter connector C-04 in good condition?
YES: Go to Step 11.
NO: Repair it. Then go to Step 12.

STEP 11. Check the wiring harness between TPMS receiver connector C-121 (terminal 10) and combination meter connector C-04 (terminal 11).

Connector: C-04:

Connector: C-121:

Q:Is the wiring harness between TPMS receiver connector C-121 (terminal 10) and combination meter connector C-04 (terminal 11) in good condition?
YES: Repair or replace it. Then go to Step 12.
NO: Replace the meter assembly. Then go to Step 12.

STEP 12. Retest the system.
Q:Turn the ignition switch to the "ON" position. Does the TPMS warning light illuminate for three seconds, and then go out?
YES: The procedure is complete.
NO: Repeat the troubleshooting from Step 1.