Toyota Corolla Cross: ECU Power Source Circuit
DESCRIPTION
If the ignition switch is ON, the hybrid vehicle control ECU applies current to the MREL terminal to turn the IGCT relay on. This supplies power to the +B1 terminal.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
- After the ignition switch is turned off, there may be a waiting time before disconnecting the negative (-) auxiliary battery terminal.
Click here
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- When disconnecting and reconnecting the auxiliary battery
HINT:
When disconnecting and reconnecting the auxiliary battery, there is an automatic learning function that completes learning when the respective system is used.
Click here
PROCEDURE
|
1. | CHECK HYBRID VEHICLE CONTROL ECU (+B1 VOLTAGE) |
(a) Turn the ignition switch to ON.
(b) Measure the voltage according to the value(s) in the table below.
|
*a | Component with harness connected (Hybrid Vehicle Control ECU) |
- | - |
Standard Voltage:
|
Tester Connection | Condition |
Specified Condition |
|---|---|---|
|
I249-8 (+B1) - Body ground |
Ignition switch ON |
11 to 14 V |
(c) Turn the ignition switch off.
| NG | .gif) | GO TO STEP 3 |
|
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|
2. | CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - BODY GROUND) |
(a) Disconnect the hybrid vehicle control ECU connectors.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection | Condition |
Specified Condition |
|---|---|---|
|
A192-12 (E01) - Body ground |
Always | Below 1 Ω |
|
A192-24 (E12) - Body ground |
Always | Below 1 Ω |
|
I249-1 (E1) - Body ground |
Always | Below 1 Ω |
(c) Reconnect the hybrid vehicle control ECU connectors.
| OK | | GO TO PROBLEM SYMPTOMS TABLE |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
3. | CHECK HYBRID VEHICLE CONTROL ECU (MREL TERMINAL VOLTAGE) |
(a) Turn the ignition switch to ON.
(b) Measure the voltage according to the value(s) in the table below.
|
*a | Component with harness connected (Hybrid Vehicle Control ECU) |
- | - |
Standard Voltage:
|
Tester Connection | Condition |
Specified Condition |
|---|---|---|
|
I249-10 (MREL) - Body ground |
Ignition switch ON |
11 to 14 V |
(c) Turn the Ignition switch off.
| NG | | REPLACE HYBRID VEHICLE CONTROL ECU |
|
|
4. | CHECK FUSE (PM-IGCT) |
(a) Remove the PM-IGCT fuse from the No. 1 engine room relay block and No. 1 junction block assembly.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection | Condition |
Specified Condition |
|---|---|---|
|
PM-IGCT fuse | Always |
Below 1 Ω |
(c) Install the PM-IGCT fuse.
| NG | | GO TO STEP 11 |
|
|
5. | CHECK FUSE (IGCT-MAIN NO. 1) |
(a) Remove the IGCT-MAIN NO. 1 fuse from the No. 1 engine room relay block and No. 1 junction block assembly.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection | Condition |
Specified Condition |
|---|---|---|
|
IGCT-MAIN NO. 1 fuse |
Always | Below 1 Ω |
(c) Install the IGCT-MAIN NO. 1 fuse.
| NG | | GO TO STEP 12 |
|
|
6. | INSPECT RELAY (IGCT-MAIN NO. 1) |
(a) Remove the IGCT-MAIN NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.
| (b) Measure the resistance according to the value(s) in the table below. Standard Resistance:
|
|
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(c) Install the IGCT-MAIN NO. 1 relay.
| NG | | REPLACE RELAY (IGCT-MAIN NO. 1) |
|
|
7. | CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY) |
(a) Disconnect the hybrid vehicle control ECU connector.
(b) Remove the PM-IGCT fuse from the No. 1 engine room relay block and No. 1 junction block assembly.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection | Condition |
Specified Condition |
|---|---|---|
|
I249-8 (+B1) - 2 (PM-IGCT fuse holder) |
Always | Below 1 Ω |
(d) Install the PM-IGCT fuse.
(e) Reconnect the hybrid vehicle control ECU connector.
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
8. | CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY) |
(a) Remove the IGCT-MAIN NO. 1 fuse, PM-IGCT fuse and IGCT-MAIN NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection | Condition |
Specified Condition |
|---|---|---|
|
5 (IGCT-MAIN NO. 1 relay holder) - 2 (IGCT-MAIN NO. 1 fuse holder) |
Always | Below 1 Ω |
|
3 (IGCT-MAIN NO. 1 relay holder) - 1 (PM-IGCT fuse holder) |
Always | Below 1 Ω |
(c) Install the IGCT-MAIN NO. 1 fuse, PM-IGCT fuse and IGCT-MAIN NO. 1 relay.
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
9. | CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY) |
(a) Disconnect the hybrid vehicle control ECU connector.
(b) Remove the IGCT-MAIN NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection | Condition |
Specified Condition |
|---|---|---|
|
I249-10 (MREL) - 1 (IGCT-MAIN NO. 1 relay holder) |
Always | Below 1 Ω |
|
I249-10 (MREL) or 1 (IGCT-MAIN NO. 1 relay holder) - Body ground and other terminals |
Always | 10 kΩ or higher |
(d) Install the IGCT-MAIN NO. 1 relay.
(e) Reconnect the hybrid vehicle control ECU connector.
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
10. | CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY - BODY GROUND) |
(a) Remove the IGCT-MAIN NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection | Condition |
Specified Condition |
|---|---|---|
|
2 (IGCT-MAIN NO. 1 relay holder) - Body ground |
Always | Below 1 Ω |
(c) Install the IGCT-MAIN NO. 1 relay.
| OK | | CHECK FOR INTERMITTENT PROBLEMS |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
11. | CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY) |
(a) Remove the PM-IGCT fuse from the No. 1 engine room relay block and No. 1 junction block assembly.
(b) Disconnect the hybrid vehicle control ECU connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection | Condition |
Specified Condition |
|---|---|---|
|
I249-8 (+B1) or 2 (PM-IGCT fuse holder) - Body ground and other terminals |
Always | 10 kΩ or higher |
(d) Reconnect the hybrid vehicle control ECU connector.
(e) Install the PM-IGCT fuse.
| OK | | REPLACE FUSE (IGCT SCENE) |
| NG | | GO TO STEP 13 |
|
12. | CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY) |
(a) Remove the IGCT-MAIN NO. 1 fuse, PM-IGCT fuse and IGCT-MAIN NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection | Condition |
Specified Condition |
|---|---|---|
|
5 (IGCT-MAIN NO. 1 relay holder) or 2 (IGCT-MAIN NO. 1 fuse holder) - Body ground and other terminals |
Always | 10 kΩ or higher |
|
3 (IGCT-MAIN NO. 1 relay holder) or 1 (PM-IGCT fuse holder) - Body ground and other terminals |
Always | 10 kΩ or higher |
(c) Install the IGCT-MAIN NO. 1 fuse, PM-IGCT fuse and IGCT-MAIN NO. 1 relay.
| OK | | REPLACE FUSE (IGCT-MAIN NO. 1) |
| NG | | GO TO STEP 14 |
|
13. | REPAIR OR REPLACE HARNESS OR CONNECTOR |
| NEXT | | REPLACE FUSE (IGCT-MAIN NO. 1) |
|
14. | REPAIR OR REPLACE HARNESS OR CONNECTOR |
| NEXT | | REPLACE FUSE (IGCT-MAIN NO. 1) |
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