Inspection Procedure A-2
Communication with the Column Switch (Column-ECU) is ImpossibleColumn Switch Power Supply And SWS Communication Circuit:
Connectors:
CIRCUIT OPERATION
- The power supply to the column switch is provided by the battery and the ignition switch (IG1).
- If the power supply system from the battery is defective, the system operates by the power supply from the ignition switch (IG1).
TECHNICAL DESCRIPTION (COMMENT)
The power supply circuit to the column switch (column-ECU) may be defective. If the battery power supply circuit (terminal No. 1 of the column switch) to the ECU is damaged, also check the power supply circuit from the ignition switch (IG1) (terminal No. 9 of the column switch), and repair if necessary.
TROUBLESHOOTING HINTS
- Malfunction of the ETACS-ECU
- Malfunction of the column switch
- Damaged harness wires or connectors
DIAGNOSIS
Required Special Tools:
- MB991223: Test Harness Set
- MB991502: Scan Tool (MUT-II)
- MB991862: SWS monitor kit
STEP 1. Use scan tool to select "ECU CHECK" on the SWS monitor display.
Check the following ECUs:
- ETACS-ECU
- column-ECU
CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502. Also connect SWS monitor kit MB991862 after turning on scan tool MB991502.
1. Connect scan tool MB991502 to the data link connector.
2. Connect SWS monitor kit MB991862 to the column switch connector.
3. When the ignition switch is turned to the "LOCK" (OFF) position, scan tool MB991502 should show "OK" on the "ECU CHECK" menu.
Q: Are "OK" displayed on the "ETACS ECU" and "COLUMN ECU" menu?
"OK" are displayed for all the items : Go to STEP 2
"NG" is displayed on the "COLUMN ECU" menu : Go to Step 12.
"NG" is displayed on the "ETACS ECU" menu : Refer to Inspection Procedure A-3 "Communication with ETACS-ECU is impossible."
"NG" are displayed for all the items : Refer to Inspection Procedure A-3 "Communication with ETACS-ECU is impossible."
STEP 2. Check column switch connector C-206 for damage.
Q: Is column switch connector C-206 in good condition?
YES: Go to STEP 3.
NO: Repair or replace the connector. The system should communicate with the column switch (column-ECU) normally.
STEP 3. Check at column switch connector C-206 by backprobing in order to check the power supply circuit to the column switch (through the battery).
1. Measure at column switch connector C-206 without disconnecting the connector.
2. Measure the voltage between terminal 1 and ground by backprobing.
- The measured value should be approximately 12 volts (battery positive voltage).
Q: Does the measured voltage correspond with this range?
YES: Go to Step 6.
NO: Go to Step 4.
STEP 4. Check column switch connector C-206 for damage.
Q: Is column switch connector C-206 in good condition?
YES: Go to Step 5.
NO: Repair or replace the connector. Refer to Harness Connector Inspection. The system should communicate with the column switch (column-ECU) normally.
STEP 5. Check the wiring harness between column switch connector C-206 and the battery.
NOTE: Also check joint connector C-05 and intermediate connector C-129. If joint connector C-05 or intermediate connectors C-129 is damaged, repair or replace the connector as described in Harness Connector Inspection.
Q: Is the wiring harness between column switch connector C-206 and the battery in good condition?
YES: No action to be taken.
NO: Repair the wiring harness. The system should communicate with the column switch (column-ECU) normally.
STEP 6. Measure at column switch connector C-206 in order to the ground circuit to the column switch.
1. Disconnect column switch connector C-206, and measure at the wiring harness side.
2. Measure the resistance value between terminal 4 and ground.
- The measured value should be 2 Ohm or less.
Q: Does the measured resistance value correspond with this range?
YES: Go to Step 9.
NO: Go to Step 7.
STEP 7. Check column switch connector C-206 for damage.
Q: Is column switch connector C-206 in good condition?
YES: Go to Step 8.
NO: Repair or replace the connector. Refer to Harness Connector Inspection. The system should communicate with the column switch (column-ECU) normally.
STEP 8. Check the wiring harness between column switch connector C-206 and the ground.
NOTE: Also check joint connector C-06. If joint connector C-06 is damaged, repair or replace the connector as described in Harness Connector Inspection.
Q: Is the wiring harness between column switch connector C-206 and the ground in good condition?
YES: No action to be taken.
NO: Repair the wiring harness. The system should communicate with the column switch (column-ECU) normally.
STEP 9. Check column switch connector C-206 and ETACS-ECU connector C-228 for damage.
Q: Are column switch connector C-206 and ETACS-ECU connector C-228 in good condition?
YES: Go to Step 10.
NO: Repair or replace the connector. Refer to Harness Connector Inspection. The system should communicate with the column switch (column-ECU) normally.
STEP 10. Check the wiring harness between column switch connector C-206 and ETACS-ECU connector C-228.
Q: Is the wiring harness between column switch connector C-206 and ETACS-ECU connector C-228 in good condition?
YES: Go to Step 11.
NO: Repair the wiring harness. The system should communicate with the column switch (column-ECU) normally.
STEP 11. Check column switch connector C-206 and ETACS-ECU connector C-228 for damage.
Q: Are column switch connector C-206 and ETACS-ECU connector C-228 in good condition?
YES: Go to Step 12.
NO: Repair or replace the connector. Refer to Harness Connector Inspection. The system should communicate with the column switch (column-ECU) normally.
STEP 12. Check the wiring harness between column switch connector C-206 and ETACS-ECU connector C-228.
Q: Is the wiring harness between column switch connector C-206 and ETACS-ECU connector C-228 in good condition?
YES: Go to Step 13.
NO: Repair the wiring harness. The system should communicate with the column switch (column-ECU) normally.
STEP 13. Replace the ETACS-ECU.
1. Replace the column switch.
2. The system should communicate with the column switch (column-ECU) normally.
Q: Can the system communicate with the column switch (column-ECU)?
YES: No action to be taken.
NO: Replace the ETACS-ECU. The system should communicate with the column switch (column-ECU) normally.