2019 Toyota Highlander Hybrid LE – Temperature Gauge Reads Hot With B1503
- Aug 16
- 1 min read
CUSTOMER CONCERN
The coolant-temperature gauge reads full hot and the combination meter stores DTC B1503. The exhaust temperature switch has already been replaced, but the code immediately returns and both switch wires measure 0 volts with the switch disconnected.
CAUSE
Rodent damage chewed through the exhaust-temperature-switch wiring beneath the vehicle near the floor area.
CORRECTION
Repair the damaged exhaust-temperature-switch wiring, clear DTC B1503, and verify the temperature gauge reads normally and the code does not return.