DTC P0A1B-788: Drive Motor "A" Control Module: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Enter the following menus: Powertrain/Hybrid Control/Trouble Codes.
4. Check if DTCs are output.

   Result

   Result	Proceed to
   P0A1B-788 only is output.	A
   Any of the following DTCs are also output.	B

   DTC No.	Relevant Diagnosis
   U0110-159, 160, 656, 657	Lost Communication with Drive Motor Control Module

5. Turn the power switch off.

B → See step   10 

A: Go to next step 

NG → CONNECT SECURELY 

OK: Go to next step 

1. Check that the service plug grip is not installed.
   NOTE: After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.
2. Turn the power switch off.
3. Disconnect the low voltage connector A59 from the inverter with converter assembly.
4. Remove the IGCT relay from the engine room junction block assembly.
5. Measure the resistance according to the value(s) in the table below.
   Fig 1: Identifying Engine Room Junction Block Assembly And IGCT Relay

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Inverter with Converter Assembly)
   *2	Engine Room Junction Block Assembly
   *3	IGCT Relay

   Standard Resistance (Check for open)

   Tester Connection	Switch Condition	Specified Condition
   A59-31 (+B) - IGCT relay terminal 5	Power switch off	Below 1 Ω
   A59-30 (+B2) - IGCT relay terminal 5	Power switch off	Below 1 Ω
   A59-11 (GND1) - Body ground	Power switch off	Below 1 Ω
   A59-10 (GND2) - Body ground	Power switch off	Below 1 Ω

   Standard Resistance (Check for short)

   Tester Connection	Switch Condition	Specified Condition
   A59-31 (+B) or A59-30 (+B2) - Body ground and other terminals	Power switch off	10 kΩ or higher

   NOTE: Do not apply excessive force when using the probes of the tester to perform the inspection. If excessive force is used, the terminals will be damaged.
6. Install the IGCT relay.
7. Connect the inverter with converter assembly connector.

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Check that the service plug grip is not installed.
   NOTE: After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.
2. Check that the bolts for the generator cable are tightened to the specified torque, the generator cable is connected securely, and there are no contact problems.
   Fig 2: Identifying Generator Cable Z10 & Inverter With Converter Assembly

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Specified Condition

   T=8.0 N*m {82 kgf*cm, 71 in.*lbf}

   NOTE: Make sure that the tightening torque of the bolts is between 6.4 and 9.6 N*m (65 and 98 kgf*cm, 57 and 85 in.*lbf).
3. Check for arc marks at the terminals for the generator cable.

   Result

   Result		Proceed to
   The terminals are connected securely and there are no contact problems.	There are no arc marks.	A
   The terminals are not connected securely and there is a contact problem.	There are arc marks.	B
   The terminals are not connected securely and there is a contact problem.	There are no arc marks.	C
   The terminals are connected securely and there are no contact problems.	There are arc marks.	B

B → REPLACE MALFUNCTIONING PARTS 

C → CONNECT SECURELY 

A: Go to next step 

1. Check that the service plug grip is not installed.
   NOTE: After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.
2. Check that the bolts for the motor cable are tightened to the specified torque, the motor cable is connected securely, and there are no contact problems.
   Fig 3: Identifying Motor Cable Z8 From Inverter With Converter Assembly

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Specified Condition

   T=8.0 N*m {82 kgf*cm, 71 in.*lbf}

   NOTE: Make sure that the tightening torque of the bolts is between 6.4 and 9.6 N*m (65 and 98 kgf*cm, 57 and 85 in.*lbf).
3. Check for arc marks at the terminals for the motor cable.

   Result

   Result		Proceed to
   The terminals are connected securely and there are no contact problems.	There are no arc marks.	A
   The terminals are not connected securely and there is a contact problem.	There are arc marks.	B
   The terminals are not connected securely and there is a contact problem.	There are no arc marks.	C
   The terminals are connected securely and there are no contact problems.	There are arc marks.	B

B → REPLACE MALFUNCTIONING PARTS 

C → CONNECT SECURELY 

OK: Go to next step 

1. Check that the service plug grip is not installed.
   NOTE: After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.
2. Disconnect the generator (MG1) cable and motor (MG2) cable from the inverter with converter assembly.
3. Check MG1 for an interphase short using a milliohmmeter.
   Fig 4: Identifying Z10 Hybrid Vehicle Transaxle Assembly & Shielded Wire Ground

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. Using a milliohmmeter, measure the resistance according to the value(s) in the table below.

      HINT: 

      If the MG1 temperature is high, the resistance will vary greatly from the specification. Therefore, measure the resistance at least 8 hours after the vehicle is stopped.

      Standard Resistance

      Tester Connection	Switch Condition	Specified Condition
      z10-2 (U) - z10-1 (V)	Power switch off	63.0 to 69.0 mΩ
      z10-1 (V) - z10-3 (W)	Power switch off	60.0 to 66.0 mΩ
      z10-3 (W) - z10-2 (U)	Power switch off	60.0 to 66.0 mΩ

      TEXT IN ILLUSTRATION
      
      

      *1	Generator Cable
      *2	Shield Ground

      HINT: 

      To correct the variation of the measured resistance due to temperature, use the following formula to calculate the resistance at 68°F (20°C).

      • R20 = Rt / {1 + 0.00393 X (T - 20)}

      The calculation is based on the following:

      • R20: Resistance at 68°F (20°C) (mΩ)
      • Rt: Measured resistance (mΩ)
      • T: Temperature when the resistance is measured (°C)
4. Using a megohmmeter set to 500 V, measure the resistance according to the value(s) in the table below.
   NOTE: Be sure to set the megohmmeter to 500 V when performing this test. Using a setting higher than 500 V can result in damage to the component being inspected.

   Standard Resistance

   Tester Connection	Switch Condition	Specified Condition
   z10-2 (U) - Body ground and shield ground	Power switch off	100 MΩ or higher
   z10-1 (V) - Body ground and shield ground	Power switch off	100 MΩ or higher
   z10-3 (W) - Body ground and shield ground	Power switch off	100 MΩ or higher

5. Connect the generator cable and motor cable.

NG → See step   8 

OK: Go to next step 

1. Check that the service plug grip is not installed.
   NOTE: After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.
2. Disconnect the generator (MG1) cable and motor (MG2) cable from the inverter with converter assembly.
3. Check MG2 for an interphase short using a milliohmmeter.
   Fig 5: Identifying Hybrid Vehicle Transaxle Assembly & Shielded Wire Ground

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. Using a milliohmmeter, measure the resistance according to the value(s) in the table below.

      HINT: 

      If the MG2 temperature is high, the resistance will vary greatly from the specification. Therefore, measure the resistance at least 8 hours after the vehicle is stopped.

      Standard Resistance

      Tester Connection	Switch Condition	Specified Condition
      z8-2 (U) - z8-1 (V)	Power switch off	72.5 to 79.5 mΩ
      z8-1 (V) - z8-3 (W)	Power switch off	69.5 to 76.5 mΩ
      z8-3 (W) - z8-2 (U)	Power switch off	69.5 to 76.5 mΩ

      TEXT IN ILLUSTRATION
      
      

      *1	Motor Cable
      *2	Shield Ground

      HINT: 

      To correct the variation of the measured resistance due to temperature, use the following formula to calculate the resistance at 68°F (20°C).

      • R20 = Rt / {1 + 0.00393 X (T - 20)}

      The calculation is based on the following:

      • R20: Resistance at 68°F (20°C) (mΩ)
      • Rt: Measured resistance (mΩ)
      • T: Temperature when the resistance is measured (°C)
4. Using a megohmmeter set to 500 V, measure the resistance according to the value(s) in the table below.
   NOTE: Be sure to set the megohmmeter to 500 V when performing this test. Using a setting higher than 500 V can result in damage to the component being inspected.

   Standard Resistance

   Tester Connection	Switch Condition	Specified Condition
   z8-2 (U) - Body ground and shield ground	Power switch off	100 MΩ or higher
   z8-1 (V) - Body ground and shield ground	Power switch off	100 MΩ or higher
   z8-3 (W) - Body ground and shield ground	Power switch off	100 MΩ or higher

5. Connect the generator cable and motor cable.

NG → See step   8 

OK → See step   9