DTC P0A1B-94: Drive Motor "A" Control Module Unexpected Operation [11/2021 - ]: Procedure

1. Check the connection of the negative (-) and positive (+) auxiliary battery terminals.

   OK

   The terminals are connected securely and there is no contact problem.

   HINT: 

   If performing a simulation test, turn the ignition switch to ON and shake the wire harnesses vertically and horizontally before checking for DTCs.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  6

Result: 

OK 

See step  2

1. Check the installation condition of the ground wires NA and NB.

   OK

   The ground wires JA and JB are securely installed.

   HINT: 

   If performing a simulation test, turn the ignition switch to ON and shake the wire harnesses vertically and horizontally before checking for DTCs.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  7

Result: 

OK 

See step  3

1. Remove the IGCT fuse from the No. 1 engine room relay block and No. 1 junction block assembly.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   IGCT fuse	Always	Below 1 Ω

3. Reinstall the IGCT fuse.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  8

Result: 

OK 

See step  4

1. Check the IGCT relay for improper installation.

   OK

   The relay is installed securely.

   HINT: 

   If performing a simulation test, turn the ignition switch to ON and gently vibrate the IGCT relay with a finger before checking for DTCs.

2. Remove the IGCT relay from the No. 1 engine room relay block and No. 1 junction block assembly.
3. Measure the resistance according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *1	IGCT Relay

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   3 - 5	Auxiliary battery voltage not applied between terminals 1 and 2	10 kΩ or higher
   	Auxiliary battery voltage applied between terminals 1 and 2	Below 1 Ω

4. Install the IGCT relay.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  9

Result: 

OK 

See step  5

1. Check for DTCs.

   HINT: 

   Check the DTCs that were output when the vehicle was brought to the workshop.

   Powertrain > Hybrid Control > Trouble Codes 

   Result

   Result	Proceed to
   P0A1B-94 only is output.	A
   DTCs except P0A1B-94 are output.	B

2. Turn the ignition switch off.

Result: 

A 

REFER TO REPLACE INVERTER WITH CONVERTER ASSEMBLY PARTS. Refer to  DTC CHECK / CLEAR [11/2021 - ] 

Result: 

B 

GO TO DTC CHART (HYBRID CONTROL SYSTEM). Refer to  DIAGNOSTIC TROUBLE CODE CHART [11/2021 - 03/2024]  , or Refer to  DIAGNOSTIC TROUBLE CODE CHART [03/2024 - ] 

Result

Result: 

NEXT 

See step  10

Result

Result: 

NEXT 

See step  10

Result

Result: 

NEXT 

See step  10

Result

Result: 

NEXT 

See step  10

See step  3

Result

Result: 

NEXT 

See step  11

1. Turn the ignition switch to ON and wait for 2 minutes or more.
2. Turn the ignition switch off.

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  12

1. Check for DTCs.

   Powertrain > Hybrid Control > Trouble Codes 

   Result

   Result	Proceed to
   No DTCs are output.	A
   P0A1B-94 only is output.	B
   DTCs except P0A1B-94 are output.	C

2. Turn the ignition switch off.

Result: 

A 

END 

Result: 

B 

REFER TO REPLACE INVERTER WITH CONVERTER ASSEMBLY PARTS. Refer to  DTC CHECK / CLEAR [11/2021 - ] 

Result: 

C 

GO TO DTC CHART (HYBRID CONTROL SYSTEM). Refer to  DIAGNOSTIC TROUBLE CODE CHART [11/2021 - 03/2024]  , or Refer to  DIAGNOSTIC TROUBLE CODE CHART [03/2024 - ]