P237F is not about wiring of the drive but about the result: the bypass flap A of the exhaust heat recovery unit was commanded, yet the effect the module expects does not appear. Ford judges this partly by temperatures, which is why SSM 52543 for the full hybrids F-150 3.5L (from 2021), Explorer 3.3L and Escape 2.5L (from 2020) and Maverick 2.5L (from 2022), all through 2024, first sends technicians to the connectors of exhaust coolant temperature sensors 3 and 4 – damaged seals, corrosion or water there can set P237F without a bad valve, so the heat exchanger need not be replaced. TSB 24-2173 fixes false P237F on 2024 Mavericks built up to 10 April 2024 with a PCM update. SSM 53003 covers a worn actuator on the F-150. The MIL comes on, driving is unaffected.
Medium severity. Can I keep driving?You can usually keep driving in the short term. If you smell exhaust fumes in the cabin, stop driving and ventilate the car.
Symptoms
- Check engine light on
- No effect on drivability
- Often stored together with P2C23
Most likely causes
- Water, corrosion or torn seal at the exhaust coolant temperature sensor 3/4 connectors (Ford SSM 52543)
- PCM calibration setting the code falsely (2024 Maverick, TSB 24-2173)
- Bypass actuator or flap sluggish, sticking or worn
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It affects emissions.
What each character of P237F means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 3: Ignition and misfires
- 7F: Specific fault in that system
Frequently asked questions
Can I keep driving with code P237F?
You can usually keep driving in the short term. If you smell exhaust fumes in the cabin, stop driving and ventilate the car.
What causes code P237F?
The most common causes are: water, corrosion or torn seal at the exhaust coolant temperature sensor 3/4 connectors (Ford SSM 52543); pCM calibration setting the code falsely (2024 Maverick, TSB 24-2173); bypass actuator or flap sluggish, sticking or worn.
Related codes
- P237CExhaust Heat Exchanger Exhaust Bypass Valve A Control Circuit/Open
- P237DExhaust Heat Exchanger Exhaust Bypass Valve A Control Circuit Low
- P237EExhaust Heat Exchanger Exhaust Bypass Valve A Control Circuit High
- P23A5Exhaust Heat Exchanger Exhaust Bypass Valve B Control Performance
- P2C23Exhaust Heat Exchanger Exhaust Bypass Valve A Position Sensor Performance
- P2C22Exhaust Heat Exchanger Exhaust Bypass Valve A Position Sensor Circuit
Sources
- static.nhtsa.gov: MC 11000295 0001
- static.nhtsa.gov: MC 11001576 0001
- static.nhtsa.gov: MC 11008695 0001
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.