Powertrain, generic · Fuel and air metering (injector circuit)

P0237 Turbocharger/Supercharger Boost Sensor A Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Boost sensor A measures the absolute pressure between charge air cooler and throttle – GM calls it TIAP, Ford TIP – usually combined with an intake air temperature sensor; its voltage rises with pressure. With the ignition on and the engine stopped it must read the same as manifold and barometric pressure. P0237 means the signal voltage is below its lower limit: GM below 14.4 % of 5 V (about 50 kPa) for roughly 4 s with the warning light in the first trip, Ford below 0.19 V for 5 s, Saab's V6 below 0.30 V for 1 s. Causes are a signal wire shorted to ground, an open 5 V reference or a failed sensor. Saab's 1.6 turbo only lights a service lamp for this code. With a sensor fault boost control is switched off and only the base boost of the wastegate spring remains, with a clear loss of power.

Likely causes

Signal or 5 V reference wire open or shorted to ground
Connector unplugged or corroded
Sensor faulty internally
5 V reference pulled down by another sensor
Engine module

Symptoms

  • Check engine light on
  • Clear loss of power, only base boost
  • Boost reading implausible in a scan tool

Repair estimate

DifficultyEasyDIY possible
Parts and labour€30–200
Time0.3–1.5 h

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

Parts involved

boost pressure sensor asensor wiringcharge air hoses

Related codes

P0238P0236P025EP0235P0241P0107

References: law.cornell.edu, gsi.ext.gm.com, fordservicecontent.com, newtonnet.co.uk.