Inspection Procedure 7: DC/DC Converter Power Supply System Check <Vehicles with AS&G system>
| caution | Even if diagnosis code No. B1351, B1352, B1353, B1355,
or B1356 is output to the AS&G-ECU, do not assume that this means a DC/DC
converter or AS&G-ECU malfunction. Always check the DC/DC converter power
supply circuit. |
PROBABLE CAUSES
- Malfunction of battery
- Damaged wiring harness and connectors
- Malfunction of DC/DC converter
DIAGNOSIS PROCEDURE |
STEP 1. Battery test |
| Check the battery state. |
Q.
Is the check result normal?
|
 Go to Step 2. |
|
 Replace the battery. |
|
STEP 2. Check the fuse. |
| Check the state of fuse No.12 (in the ETACS-ECU). |
Q.
Is the check result normal?
|
| Go to Step 4. |
|
| Go to Step 3. |
|
STEP 3. Recheck the fuse. |
| (1)Replace fuse No.12 (in the ETACS-ECU). |
| (2)Turn the ignition switch to the "ON" position, wait at least 1 minute, and then
switch it "OFF". |
| (3)Check fuse No.12 (in the ETACS-ECU). |
Q.
Is the check result normal?
|
| The inspection is complete. |
|
| Repair the power supply line (ignition switch side) between the DC/DC converter
connector and the ETACS-ECU connector. Then, replace the fuse. |
|
STEP 4. Perform voltage measurement at DC/DC converter connector (power supply terminal [ignition switch side]). |
| (1)Disconnect the connector, and measure at the wiring harness side. |
| (2)Measure the voltage between the DC/DC converter connector (power supply terminal [ignition
switch side]) and body earth. |
| (3)Turn the ignition switch to the "ON" position. OK: System voltage |
Q.
Is the check result normal?
|
| Go to Step 6. |
|
| Go to Step 5. |
|
STEP 5. Check for open circuit or short to earth in power supply line (ignition switch side) between the DC/DC converter connector and ETACS-ECU connector. |
Q.
Is the check result normal?
|
| Intermittent malfunction. |
|
| Repair the connector(s) or wiring harness. |
|
STEP 6. Perform resistance measurement at the DC/DC converter connector (earth terminal). |
| (1)Disconnect the connector, and measure at the wiring harness side. |
| (2)Measure the resistance between the DC/DC converter connector (earth terminal) and
body earth. OK: Continuity exist (2 Ω or less). |
Q.
Is the check result normal?
|
| Go to Step 8. |
|
| Go to Step 7. |
|
STEP 7. Check for open circuit in earth line between the DC/DC converter connector and body earth. |
Q.
Is the check result normal?
|
| Intermittent malfunction. |
|
| Repair the connector(s) or wiring harness. |
|
STEP 8. Perform voltage measurement at DC/DC converter connector (power supply terminal [battery side]). |
| (1)Disconnect the connector, and measure at the wiring harness side. |
| (2)Measure the voltage between the DC/DC converter connector (power supply terminal [battery
side]) and body earth. OK: System voltage |
Q.
Is the check result normal?
|
| Go to Step 10. |
|
| Go to Step 9. |
|
STEP 9. Check for open circuit or short to earth in power supply line (battery side) between the DC/DC converter connector and the fusible link No.36. |
Q.
Is the check result normal?
|
| Intermittent malfunction. |
|
| Repair the connector(s) or wiring harness. |
|
STEP 10. Recheck the trouble symptom. |
Q.
Does the malfunction take place again?
|
| Replace the DC/DC converter. |
|
| The inspection is complete. |
|