DTC B1503: Exhaust Heat Management Warning Detected: Procedure

1. Set the vehicle in maintenance mode using the Techstream. Refer to INSPECTION MODE PROCEDURE .
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: 80 to 100°C (176 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 hybrid vehicle control ECU is suspected.

   OK

   Engine coolant temperature displayed on the Techstream is 80 to 100°C (176 to 212°F) after warming up.

NG → See step   5 

OK: Go to next step 

1. Disconnect the A1 connector.
2. Disconnect the F4 connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A1-2 (TWS2) - F4-26 (SW)	Always	Below 1 Ω
   A1-2 (TWS2) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Replace the temperature switch with a new or a known good one. Refer to REMOVAL .

   OK

   The operation of the combination meter assembly returns to normal.

NG → See step   4 

OK → END