DTC P0AA1-231: Hybrid Battery Positive Contactor Circuit Stuck Closed: Procedure

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

   Result

   DTC No.	Relevant Part
   P0AE2-773, 161	SMRP short
   P0ADC-226	SMRB control line
   P0A1A-156, 658, 659, 151, 155, P0A1B-511, 164, 163, 512, 193, 786, 788, 661, P0A78-266, 267, 523, 586, P0A94-442, P3004-132	VH sensor circuit
   P0A1A-200, 791, 792, 793, P0A1B-192, 168, 794, 795, 796, P0A3F-243, P0A41-245, P0A40-500, P0A4B-253, P0A4C-513, P0A4D-255	MG1 and MG2 rotation speed circuit

   HINT: 

   • Turning the power switch on (IG) with the service plug grip and inverter cover removed causes interlock switch system DTC P0A0D-350 to be output.
   • P0AA1-231 may be output due to a malfunction which causes the DTCs in the table above to be output. In this case, first troubleshoot the output DTCs in the table above. Then, perform a reproduction test to check that no DTCs are output.

YES → See step   6 

NO: Go to next step 

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Select the following menu items: Powertrain / Hybrid Control / Trouble Codes.
4. Read output DTCs.
5. Read the freeze frame data of P0AA1-231.

   Result

   Result	Proceed to
   Boost converter voltage (VL) is less than 60 V.	A
   Boost converter voltage (VL) is 60 V or more.	B

A → See step   5 

B: Go to next step 

1. Turn the power switch off and remove the service plug grip. Refer to PRECAUTION .
   Fig 1: Identifying H4 And S1 In HV Relay Assembly Component

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   NOTE:

   After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair information because this may cause a malfunction.

   HINT: 

   For the removal and installation procedures related to inspection of the HV relay assembly. Refer to REMOVAL .

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

   Standard resistance

   Tester Connection	Specified Condition
   h4-1 - s1-1	10 kΩ or more

   HINT: 

   • Leave the HV relay in the vehicle while testing to prevent the movement that occurs during removal from causing a stuck relay to return to normal.
   • If the result of reading the freeze frame data is B, the HV relay assembly must be replaced. Measuring resistance can determine that this is either a present or past malfunction.

NG → See step   4 

OK → See step   4