DTC 13
Front-ECU faultFront-ECU Power Supply And SWS Communication Circuit:
Connectors:
CIRCUIT OPERATION
- The front-ECU is energized by the battery and the ignition switch (IG2). If one of the harness wires has an open circuit, power will be supplied by the other active harness wire.
- The front-ECU communicates with other ECUs and performs control functions through the SWS communication line.
DTC SET CONDITION
This DTC is displayed when the front-ECU sends an abnormal signal to the ETACS-ECU.
TROUBLESHOOTING HINTS
- Malfunction of the front- ECU
- Malfunction of the ETACS-ECU
- Damaged harness wires or connectors
DIAGNOSIS
Required Special Tools:
- MB991223: Harness Set
- MB991502: Scan Tool (MUT-II)
STEP 1.Check the ignition switch position.
Q: Does DTC 13 set with the ignition switch at "ON" position?
YES: Go to Step 5.
NO: Go to Step 2.
STEP 2. Check the front-ECU power supply circuit (battery circuit) at the front-ECU connector A-09X.
1. Disconnect the front-ECU connector A-09X and measure at the relay box side.
2. Measure the voltage between terminal 16 and ground.
Q: Is the voltage approximately 12 volts (battery positive voltage)?
YES: Replace the front-ECU. Confirm the DTC 13 is not displayed.
NO: Go to Step 3.
STEP 3. Check the front-ECU connector A-09X for damage.
Q: Is front-ECU connector A-09X in good condition?
YES: Go to Step 4.
NO: Repair or replace it. Refer to Harness Connector Inspection. Confirm the DTC 13 is not displayed.
STEP 4. Check the harness wire between front-ECU connector A-09X and battery.
Q: Is the harness wire between front-ECU connector A-09X and battery in good condition?
YES: There is no action to be taken.
NO: Repair it. Confirm the DTC 13 is not displayed.
STEP 5. Check the front-ECU ground circuit at the front ECU connector A-09X.
1. Disconnect the front-ECU connector A-09X and measure at the relay box side.
2. Measure the resistance between terminal 1 and ground.
Q: Is the resistance less than 2 ohm?
YES: Go to Step 8.
NO: Go to Step 6.
STEP 6. Check the front-ECU connector A-09X for damage.
Q: Is front-ECU connector A-09X in good condition?
YES: Go to Step 7.
NO: Repair or replace it. Refer to Harness Connector Inspection. Confirm the DTC 13 is not displayed.
STEP 7. Check the harness wire between front-ECU connector A-09X and ground.
Q: Is the harness wire between front-ECU connector A-09X and ground in good condition?
YES: There is no action to be taken.
NO: Repair it. Confirm the DTC 13 is not displayed.
STEP 8. Check front-ECU connector A-09X and ETACS-ECU connector C-313 for damage.
Q: Are front-ECU connector A-09X and ETACS-ECU connector C-313 In good condition?
YES: Go to Step 9.
NO: Repair or replace them. Refer to Harness Connector Inspection. Confirm the DTC 13 is not displayed.
STEP 9. Check the harness wires between front-ECU connector A-09X and ETACS-ECU connector C-313.
NOTE: After checking intermeditate connector C-209 and joint connector C-141, check the wires. If intermeditate connector C-209 and joint connector C-141 are damaged, repair or replace them. Refer to Harness Connector Inspection.
Q: Are the harness wires between front-ECU connector A09X and ETACS-ECU connector C-313 in good condition?
YES: Go to Step 10.
NO: Repair them. Confirm the DTC 13 is not displayed.
STEP 10. Replacement of ECU.
1. Replace the front-ECU.
2. Confirm the DTC 13 is not displayed.
Q: Does DTC 13 set?
YES: Replace the ETACS-ECU. Confirm the DTC 13 is not displayed.
NO: There is no action to taken.