DTC B1503: Exhaust Heat Management Warning Detected [08/2014 - ]: Procedure

1. Set the vehicle in the maintenance mode using the Techstream (See article. Refer to INSPECTION MODE PROCEDURE [08/2014 - ] ).
2. Connect the Techstream to the DLC3.
3. Turn the power switch on (IG).
4. Turn the Techstream on.
5. Enter the following menus: Body Electrical / Combination Meter / Data List.
6. Check the values by referring to the table below.
   COMBINATION METER
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Coolant Temperature	Engine coolant temperature/-40 to 127.5°C (-40 to 261.5°F)	After warming up: 75 to 100°C (167 to 212°F)	-

   HINT: 

   • The coolant temperature value in this inspection is the data sent from the engine coolant temperature sensor for the SFI system.
   • When the Data List values do not match, a signal output error of the ECM is suspected.

   OK

   Engine coolant temperature displayed on the Techstream is 75 to 100°C (167 to 212°F) after warming up.

Result:  NG

NG 

GO TO EXHAUST HEAT RECIRCULATION SYSTEM 

(See article. Refer to PROBLEM SYMPTOMS TABLE [08/2014 - ] )

Result:  OK

OK 

See step  2

1. Disconnect the F2 connector.
2. Disconnect the H19 connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   F2-2 (TWS3) - H19-26 (TWS3)	Always	Below 1 Ω
   F2-1 (E2) - H19-34 (E2)	Always	Below 1 Ω
   F2-2 (TWS3) or H19-26 (TWS3) - Body ground	Always	10 kΩ or higher

Result:  NG

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result:  OK

OK 

See step  3

1. Remove the engine coolant temperature sensor (See article. Refer to REMOVAL [08/2014 - ] ).

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   1 (E2) - 2 (TWS3)	Temperature is 20°C (68°F)	2.32 to 2.59 kΩ
   1 (E2) - 2 (TWS3)	Temperature is 80°C (176°F)	0.310 to 0.326 kΩ

   TEXT IN ILLUSTRATION
   
   

   *a	Component without harness connected (Engine Coolant Temperature Sensor)
   *b	Resistance kΩ
   *c	Temperature °C (°F)

Result:  OK

OK 

REPLACE COMBINATION METER ASSEMBLY 

(See article. Refer to REMOVAL [08/2014 - ] )

Result:  NG

NG 

REPLACE ENGINE COOLANT TEMPERATURE SENSOR 

(See article. Refer to REMOVAL [08/2014 - ] )