DTC B1503: Exhaust Heat Management Warning Detected [11/2015 - ]: Procedure

1. Set the vehicle in maintenance mode using the Techstream (Refer to INSPECTION MODE PROCEDURE [11/2015 - ] ).
2. Connect the Techstream to the DLC3.
3. Turn the ignition switch to 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/0 to 127.5°C (0 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 

REFER TO EXHAUST HEAT RECIRCULATION SYSTEM 

Refer to PROBLEM SYMPTOMS TABLE [11/2015 - ] )

Result: 

OK 

See step  2

1. Disconnect the A30 water temperature sensor connector.
2. Disconnect the G1 combination meter assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A30-2 (TWS3) - G1-15 (TWS3)	Always	Below 1 Ω
   A30-1 (E2) - G1-36 (E2)	Always	Below 1 Ω
   A30-2 (TWS3) or G1-15 (TWS3) - Body ground	Always	10 kΩ or higher

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

1. Remove the water temperature sensor (Refer to REMOVAL [11/2015 - ] ).

   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
   A30-1 (E2) - A30-2 (TWS3)	Temperature is 20°C (68°F)	2.32 to 2.59 kΩ
   A30-1 (E2) - A30-2 (TWS3)	Temperature is 80°C (176°F)	0.310 to 0.326 kΩ

   TEXT IN ILLUSTRATION
   
   

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

Result: 

OK 

REPLACE COMBINATION METER ASSEMBLY 

Refer to REMOVAL [11/2015 - ] )

Result: 

NG 

REPLACE ENGINE COOLANT TEMPERATURE SENSOR 

Refer to REMOVAL [11/2015 - ] )