Some 2016-2019 Toyota Prius and 2017-2019 Prius Prime vehicles may exhibit one or more of the following conditions due to coolant leakage at the front exhaust pipe heat exchanger:
- Low coolant level
- MIL on with DTC P148F00
- Poor heater performance
The front exhaust pipe with heat exchanger assembly has been updated. Old part numbers 17410-37B52, 17410-37B50 and 17410-37A00 have been replaced with new part number 17410-37D40. Exhaust pipe gaskets 17451-0D140 and 17451-F2010 are also required.
With the engine off and exhaust system cold, unbolt and disconnect the rear exhaust pipe assembly from the front exhaust pipe assembly at the mating flange. Perform a visual inspection inside the exhaust pipe for signs of coolant leakage into the exhaust system. If no visible signs of coolant leakage are found, pressurize the cooling system to 17 psi and recheck for visible signs of leakage. Using a borescope into the front exhaust pipe may aid in leak identification. If leakage is found, remove the front exhaust pipe assembly and install the newly upgraded pipe assembly.
