DTC P0A1B-94: Drive Motor "A" Control Module Unexpected Operation [12/2023 - ]: 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 wire YC and YD.

   OK

   The ground wire YC and YD is 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

Pre-procedure1

• Remove the IGCT fuse from the No. 1 engine room relay block and No. 1 junction block assembly.

• Measure the resistance according to the value(s) in the table below.

  Standard Resistance

  Tester Connection	Condition	Specified Condition	Result
  IGCT fuse	Always	Below 1 Ω	Ω

  Result

  Proceed to
  OK
  NG

Post-procedure1

• Reinstall the IGCT fuse.

Result: 

NG 

See step  8

Result: 

OK 

See step  4

Pre-procedure1

• Check the IGCT NO. 1 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 NO. 1 relay with a finger before checking for DTCs.

• Remove the IGCT NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

• Measure the resistance according to the value(s) in the table below.

  Standard Resistance

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

  Result

  Proceed to
  OK
  NG

  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

  *1	IGCT NO. 1 Relay

Post-procedure1

• Install the IGCT NO. 1 relay.

Result: 

NG 

See step  9

Result: 

OK 

See step  5

Pre-procedure1

• None.

• 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
  Only P0A1B-94 is output	A
  None of the above conditions are met	B

Post-procedure1

• Turn the ignition switch off.

Result: 

A 

REPLACE HYBRID MOTOR CONTROL INVERTER ASSEMBLY. Refer to  REMOVAL [12/2023 - ] 

Result: 

B 

GO TO DTC CHART (HYBRID CONTROL SYSTEM). Refer to  DIAGNOSTIC TROUBLE CODE CHART [12/2023 - ] 

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

Pre-procedure1

• 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.

  Result

  Proceed to
  NEXT

Post-procedure1

• Turn the ignition switch off.

Result: 

NEXT 

See step  12

Pre-procedure1

• None.

• Check for DTCs.

  Powertrain > Hybrid Control > Trouble Codes 

  Result

  Result	Proceed to
  DTCs are not output	A
  Only P0A1B-94 is output	B
  None of the above conditions are met	C

Post-procedure1

• Turn the ignition switch off.

Result: 

A 

END 

Result: 

B 

REPLACE HYBRID MOTOR CONTROL INVERTER ASSEMBLY. Refer to  REMOVAL [12/2023 - ] 

Result: 

C 

GO TO DTC CHART (HYBRID CONTROL SYSTEM). Refer to  DIAGNOSTIC TROUBLE CODE CHART [12/2023 - ]