Powertrain, generic (extended)

P237E Exhaust Heat Exchanger Exhaust Bypass Valve A Control Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P237E is logged when the driver for exhaust bypass flap A on a heat recovery unit sees a control voltage above its expected range. The likely story is a short from the control wire to a supply feed or an actuator whose internal driver has failed in a way that pulls the line up. The flap then no longer follows the warm-up strategy. Ford is the one maker that names the code publicly, and only once: SSM 53003 lists P237E together with P237C, P237D, P237F, P2C22 and P2C23 for 2021–2023 F-150 hybrids with the 3.5L PowerBoost and blames the actuator mounted on the heat exchanger, which is replaced with a service kit after normal diagnosis. A lit MIL is reported. P237D is the low-side mirror image and P23A4 the same fault on valve B; a high signal rarely heals by itself.

Likely causes

Heat exchanger bypass actuator with failed internal driver (Ford F-150 SSM 53003)
Control wire shorted to a supply circuit in the harness
Heat-damaged connector with bridged pins

Symptoms

  • Check engine light on
  • Cabin heat may build up later on cold days

Repair estimate

DifficultyHardWorkshop job
Parts and labour€80–900
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

exhaust bypass valve aexhaust heat recovery actuator

Related codes

P237CP237DP237FP23A4P2C23

References: static.nhtsa.gov, en.wikipedia.org.