DTC 22
DTC 22: Stoplight Switch SystemStoplight Switch System Circuit Part 1:
Stoplight Switch System Circuit Part 2:
CIRCUIT OPERATION
- Battery positive voltage is supplied to the stoplight switch (terminal 2 and 3).
- When the brake pedal is depressed, battery positive voltage is applied to the ECM
DTC SET CONDITIONS Check Condition
- The "CRUISE" indicator light illuminates.
Judgement Criteria
- Short in stop light switch circuit.
- Open circuit in the brake switch circuit (between PCM terminal 54 and ground).
TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CASE:)
- Malfunction of the stoplight switch.
- Damaged harness or connector.
- Malfunction of the ECM
- Malfunction of the PCM .
DIAGNOSIS
Required Special Tools:
- MB991958: Scan tool (MUT-III sub assembly)
- MB991824: V.C.I.
- MB991827: MUT-III USB cable
- MB991911: MUT-III main harness B
- MB991223: Harness set
- MB992006: Extra Fine Probe
STEP 1. Using scan tool MB991958, check data list item 05: Stoplight Switch.
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. Set scan tool MB991958 to data reading mode.
- Item 05, Stoplight 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".
4. Turn the ignition switch to the "LOCK" (OFF) position.
5. Disconnect scan tool MB991958.
Q: Is the switch operating properly?
YES: Go to Step 14.
NO: Go to Step 2.
STEP 2. Check the stoplight operation.
Check the stoplight operation.
- When the brake pedal is depressed, the stoplight will illuminate.
- When the brake pedal is released, the stoplight does not illuminate.
Q: Is the stoplight will illuminate (when the brake pedal is depressed) and the stoplight does not illuminate (when the brake pedal is released)?
YES: Go to Step 3.
NO: Go to Step 6.
STEP 3. Measure the terminal voltage at ECM connector C-135
1. Do not disconnect ECM connector C-135
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between ECM connector C-135
- When the brake pedal is depressed, the voltage should measure battery positive voltage (approximately 12 volts).
- When the brake pedal is released, the voltage should measure 1 volt or less.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage battery positive voltage (approximately 12 volts) when the brake pedal is depressed and 1 volt or less when the brake pedal is released?
YES: Go to Step 13.
NO: Go to Step 4.
STEP 4. Check ECM connector C-135
Q: Are there connectors and terminals in good condition?
YES: Go to Step 5.
NO: Repair or replace the damaged components. Then go to Step 23.
STEP 5. Check the harness wire between ECM connector C-135
Q: Are there harness wires in good condition?
YES: Go to Step 13.
NO: Repair the damaged harness wire. Then go to Step 23 .
STEP 6. Measure the power supply voltage at stoplight switch connector C-102.
1. Disconnect stoplight switch connector C-102.
2. Measure the voltage between stoplight switch connector C-102 terminal 2 and ground.
- Voltage should measure battery positive voltage.
3. Connect stoplight switch connector C-102.
Q: Is the measured voltage battery positive voltage (approximately 12 volts)?
YES: Go to Step 10.
NO: Go to Step 7.
STEP 7. Check stoplight switch connector C-102 and intermediate connector C-129 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Are there connectors and terminals in good condition?
YES: Go to Step 8.
NO: Repair or replace the damaged components. Then go to Step 23.
STEP 8. Check the harness wire between stoplight switch connector C-102 terminal 2 and fuse number 10 at the relay box in engine compartment for damage.
Q: Are there harness wires in good condition?
YES: Go to Step 9.
NO: Repair the damaged harness wire. Then go to Step 23 .
STEP 9. Check the fuse number 10 at the relay box in engine compartment.
Q: Is the fuse in good condition?
YES: Go to Step 10.
NO: Check the stoplight system harness and replace the fuse. Then go to Step 23.
STEP 10. Check the stoplight switch.
1. Remove the stoplight switch.
2. Connect an ohmmeter to the stoplight switch between terminals 1 and 2.
3. Check for continuity between the terminals when the plunger of the stoplight switch is pushed in and when it is released.
4. The stoplight switch is operating properly if the circuit is open between terminals 1 and 2 when the plunger is pushed in to a depth of within 4.0 mm (0.16 inch) from the outer case edge surface, and if the resistance value is less than 2 Ohms between terminals 1 and 2 when it is released.
Q: Is the stoplight switch between terminals 1 and 2 still open circuit even with the plunger pushed in, and resistance value is less than 2 Ohms when plunger is released?
YES: Install the stoplight switch. Then go to Step 11.
NO: Replace the stoplight switch. Then go to Step 23.
STEP 11. Check stoplight switch connector C-102 and intermediate connector C-124 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Are there connectors and terminals in good condition?
YES: Go to Step 12.
NO: Repair or replace the damaged components. Then go to Step 23.
STEP 12. Check the harness wire between stoplight switch connector C-102 terminal 1 and intermediate connector C-124 terminal 14 for damage.
Q: Is the harness wire in good condition?
YES: Go to Step 13.
NO: Repair the damaged harness wire. Then go to Step 23 .
STEP 13. Using scan tool MB991958, check data list item 05: Stoplight Switch.
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. Set scan tool MB991958 to data reading mode.
- Item 05, Stoplight 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".
4. Turn the ignition switch to the "LOCK" (OFF) position. (5) Disconnect scan tool MB991958.
Q: Is the switch operating properly?
YES: Go to Step 22.
NO: Replace the ECM
STEP 14. Using scan tool MB991958, check data list item 06: Brake Switch.
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. Set scan tool MB991958 to data reading mode.
- Item 06, 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".
4. Turn the ignition switch to the "LOCK" (OFF) position. (5) Disconnect scan tool MB991958.
Q: Is the switch operating properly?
YES: Go to Step 22.
NO: Go to Step 15.
STEP 15. Measure the terminal voltage at ECM connector C-135
1. Do not disconnect ECM connector C-135
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between ECM connector C-135
- When the brake pedal is depressed, the voltage should measure battery positive voltage (approximately 12 volts).
- When the brake pedal is released, the voltage should measure 1 volt or less.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage battery positive voltage (approximately 12 volts) when the brake pedal is depressed and 1 volt or less when the brake pedal is released?
YES: Go to Step 21.
NO: Go to Step 16.
STEP 16. Check the stoplight switch.
1. Remove the stoplight switch.
2. Connect an ohmmeter to the stoplight switch between terminals 3 and 4.
3. Check for continuity between the terminals when the plunger of the stoplight switch is pushed in and when it is released.
4. The stoplight switch is operating properly if the circuit is open between terminals 3 and 4 when the plunger is released, and if resistance value is less than 2 Ohms between terminals 3 and 4 when the plunger is pushed in to a depth of within 4.5 mm (0.18 inch) from the outer case edge surface.
Q: Is the stoplight switch between terminals 3 and 4 still open circuit when the plunger is released, and resistance value is less than 2 Ohms even with the plunger is pushed in?
YES: Install the stoplight switch. Then go to Step 17.
NO: Replace the stoplight switch. Then go to Step 23.
STEP 17. Check ECM connector C-135
Q: Are there connectors and terminals in good condition?
YES: Go to Step 18.
NO: Repair or replace the damaged components. Then go to Step 23.
STEP 18. Check the harness wire between ECM connector C-135
Q: Are there harness wires in good condition?
YES: Go to Step 19.
NO: Repair the damaged harness wire. Then go to Step 23 .
STEP 19. Check stoplight switch connector C-102 and intermediate connector C-111 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Are there connectors and terminals in good condition?
YES: Go to Step 20.
NO: Repair or replace the damaged components. Then go to Step 23.
STEP 20. Check the harness wire between stoplight switch connector C-102 terminal 4 and ground for damage.
Q: Is the harness wire in good condition?
YES: Go to Step 21.
NO: Repair the damaged harness wire. Then go to Step 23 .
STEP 21. Using scan tool MB991958, check data list item 06: Brake Switch.
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. Set scan tool MB991958 to data reading mode.
- Item 06, 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".
4. Turn the ignition switch to the "LOCK" (OFF) position. (5) Disconnect scan tool MB991958.
Q: Is the switch operating properly?
YES: Go to Step 22.
NO: Replace the ECM
STEP 22. Using scan tool MB991958, read the diagnostic trouble codes.
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. Set scan tool MB991958 to read the diagnostic trouble codes.
4. Turn the ignition switch to the "LOCK" (OFF) position. (5) Disconnect scan tool MB991958.
Q: Is DTC 22 set?
YES: Replace the ECM
NO: It can be assumed that this malfunction is intermittent.
STEP 23. Using scan tool MB991958, read the diagnostic trouble codes.
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. Set scan tool MB991958 to read the diagnostic trouble codes.
4. Turn the ignition switch to the "LOCK" (OFF) position.
5. Disconnect scan tool MB991958.
Q: Is DTC 22 set?
YES: Return to Step 1.
NO: The procedure is complete.