DTC P144C: Open in Secondary Air Injection System Heater Control Circuit; DTC P144D: Short in Secondary Air Injection System Heater Control Circuit [08/2015 - ]: Procedure

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Remove the air pump heater relay (AIR PMP HTR) from the engine room relay block.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

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

Result: 

NG 

REPLACE AIR PUMP HEATER RELAY (AIR PMP HTR) 

Result: 

OK 

See step  2

1. Remove the air pump heater relay (AIR PMP HTR) from the engine room relay block.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   2 (Air pump heater relay (AIR PMP HTR)) - Body ground	Always	11 to 14 V
   5 (Air pump heater relay (AIR PMP HTR)) - Body ground

   TEXT IN ILLUSTRATION
   
   

   *1	Engine Room Relay Block
   *2	Air Pump Heater Relay (AIR PMP HTR)

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

1. Remove the air pump heater relay (AIR PMP HTR) from the engine room relay block.
2. Disconnect the C30 ECM connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   1 (Air pump heater relay (AIR PMP HTR)) - C30-21 (HAI1)	Always	Below 1 Ω
   1 (Air pump heater relay (AIR PMP HTR)) or C30-21 (HAI1) - Body ground	Always	10 kΩ or higher

Result: 

OK 

REPLACE ECM 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR