| Last Modified: 05-13-2024 | 6.11:8.1.0 | Doc ID: RM1000000026PY7 |
| Model Year Start: 2023 | Model: Corolla HV | Prod Date Range: [09/2022 - ] |
| Title: HYBRID / BATTERY CONTROL: MOTOR GENERATOR CONTROL SYSTEM (for LITHIUM-ION BATTERY with PA10): P31241F; Lost Communication between Drive Motor "A" and HV/EV ECU Circuit Intermittent; 2023 - 2025 MY Corolla HV [09/2022 - ] | ||
|
DTC |
P31241F |
Lost Communication between Drive Motor "A" and HV/EV ECU Circuit Intermittent |
DESCRIPTION
The motor generator control ECU, which is built into the inverter with converter assembly, controls the motor (MG2) based on commands from the hybrid vehicle control ECU.
The motor generator control ECU (MG ECU) monitors communication data and detects malfunctions.
|
DTC No. |
Detection Item |
DTC Detection Condition |
Trouble Area |
MIL |
Warning Indicate |
Note |
|---|---|---|---|---|---|---|
|
P31241F |
Lost Communication between Drive Motor "A" and HV/EV ECU Circuit Intermittent |
Error in reception from hybrid vehicle control ECU via serial communication (out of communication standard) detected when DTC P0C7917, P0E5717, P0D3319, P1C5D19, P1C5F19 or P1C5E19 is stored. (1 trip detection logic) |
|
Does not come on |
Master Warning: Does not come on |
SAE Code: P3124 |
CONFIRMATION DRIVING PATTERN
HINT:
After repair has been completed, clear the DTC and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.
Click here
![2023 - 2025 MY Corolla HV [09/2022 - ]; HYBRID / BATTERY CONTROL: MOTOR GENERATOR CONTROL SYSTEM (for LITHIUM-ION BATTERY with PA10): UTILITY](/t3Portal/stylegraphics/info.gif)
- Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
- Turn the ignition switch off and wait for 2 minutes or more.
- Turn the ignition switch to ON and wait for 2 minutes or more.
- Enter the following menus: Powertrain / Motor Generator / Utility / All Readiness.
-
Check the DTC judgment result.
HINT:
- If the judgment result shows NORMAL, the system is normal.
- If the judgment result shows ABNORMAL, the system has a malfunction.
- If the judgment result shows INCOMPLETE, perform the normal judgment procedure again.
WIRING DIAGRAM
Refer to the wiring diagram for the Inverter Low-voltage Circuit.
Click here
CAUTION / NOTICE / HINT
CAUTION:
Refer to the precautions before inspecting high voltage circuit.
Click here
NOTICE:
-
After the ignition switch is turned off, there may be a waiting time before disconnecting the negative (-) auxiliary battery terminal.
Click here
-
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. |
CLEAR DTC |
(a) Clear the DTCs.
Powertrain > Motor Generator > Clear DTCs
(b) Turn the ignition switch off.
|
|
2. |
CHECK DIAGNOSIS RELATED INFORMATION AND DTC OUTPUT (MOTOR GENERATOR) |
(a) Turn the ignition switch to ON and wait for 2 minutes or more.
(b) Check for DTCs.
Powertrain > Motor Generator > Utility
|
Tester Display |
|---|
|
Diagnosis Related Information |
Powertrain > Motor Generator > Trouble Codes
|
Result |
Proceed to |
|---|---|
|
P31241F is listed in Diagnosis Related Information or P31241F is output. |
A |
|
P31241F are not listed in Diagnosis Information and P31241F is not output. |
B |
(c) Turn the ignition switch off.
| B |
|
|
|
3. |
CHECK HYBRID VEHICLE CONTROL ECU (CHECK WAVEFORM) |
(a) Connect an oscilloscope between the hybrid vehicle control ECU terminals specified in the following table.
(b) Turn the ignition switch to ON.
(c) Measure the waveform.
|
*a |
Component with harness connected (Hybrid Vehicle Control ECU) |
- |
- |
|
Item |
Contents |
|---|---|
|
Tester Connection |
CH1: A161-2 (HMCH) - I3-1 (E1) CH2: A161-1 (HMCL) - I3-1 (E1) |
|
Equipment Setting |
1 V/DIV., 200 μs./DIV. |
|
Condition |
Ignition switch ON |
|
Result |
Proceed to |
|---|---|
|
The waveform appears as shown in the illustration. |
A |
|
The waveform differs from the one shown in the illustration. |
B |
HINT:
- Perform this inspection with the connector connected.
- If pulses are generated, the shape of the waveform can be assumed to be normal.
- The shape of the waveform may vary according to communication conditions.
(d) Turn the ignition switch off.
| A |
|
|
|
4. |
CHECK CONNECTOR CONNECTION CONDITION (HYBRID VEHICLE CONTROL ECU CONNECTOR) |
Click here
| NG |
|
CONNECT SECURELY |
|
|
5. |
CHECK CONNECTOR CONNECTION CONDITION (INVERTER WITH CONVERTER ASSEMBLY CONNECTOR) |
Click here
|
Result |
Proceed to |
|---|---|
|
OK |
A |
|
NG (The connector is not connected securely.) |
B |
|
NG (The terminals are not making secure contact or are deformed, or water or foreign matter exists in the connector.) |
C |
| B |
|
CONNECT SECURELY |
| C |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
6. |
CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - INVERTER WITH CONVERTER ASSEMBLY) |
CAUTION:
Be sure to wear insulated gloves.
(a) Check that the service plug grip is not installed.
NOTICE:
After removing the service plug grip, do not turn the ignition switch to ON (READY), unless instructed by the repair manual because this may cause a malfunction.
(b) Disconnect the inverter with converter assembly connector.
(c) Disconnect the hybrid vehicle control ECU connector.
(d) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
A155-29 (HMCH) - A161-2 (HMCH) |
Ignition switch off |
Below 1 Ω |
|
A155-30 (HMCL) - A161-1 (HMCL) |
Ignition switch off |
Below 1 Ω |
Standard Resistance (Check for Short):
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
A155-29 (HMCH) or A161-2 (HMCH) - Body ground and other terminals |
Ignition switch off |
10 kΩ or higher |
|
A155-30 (HMCL) or A161-1 (HMCL) - Body ground and other terminals |
Ignition switch off |
10 kΩ or higher |
(e) Connect the cable to the negative (-) auxiliary battery terminal.
(f) Turn the ignition switch to ON.
(g) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
A155-29 (HMCH) or A161-2 (HMCH) - Body ground and other terminals |
Ignition switch ON |
Below 1 V |
|
A155-30 (HMCL) or A161-1 (HMCL) - Body ground and other terminals |
Ignition switch ON |
Below 1 V |
NOTICE:
Turning the ignition switch to ON with the hybrid vehicle control ECU and inverter with converter assembly connectors disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection.
HINT:
As there might be an intermittent malfunction, inspect the following items even if the measured resistance is as specified.
Check that each connector between the inverter with converter assembly and hybrid vehicle control ECU is not loose or disconnected.
(h) Turn the ignition switch off.
(i) Reconnect the hybrid vehicle control ECU connector.
(j) Reconnect the inverter with converter assembly connector.
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
7. |
CHECK INVERTER WITH CONVERTER ASSEMBLY |
(a) Disconnect the hybrid vehicle control ECU connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
A161-2 (HMCH) - A161-1 (HMCL) |
Ignition switch off |
80 to 170 Ω |
(c) Reconnect the hybrid vehicle control ECU connector.
| OK |
|
| NG |
|
|
|