What P0237 means
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.
How the engine computer detects it
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 (7.3 psi)) 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.
Written from public technical sources and not yet checked by a mechanic. How we write these pages
Symptoms
- Check engine light on
- Clear loss of power, only base boost
- Boost reading implausible in a scan tool
Common causes
- Signal or 5 V reference wire open or shorted to ground Most likely
- Connector unplugged or corroded Most likely
- Sensor faulty internally Possible
- 5 V reference pulled down by another sensor Less likely
- Engine module Less likely
How to diagnose P0237
- Read every stored code with an OBD-II scanner. If misfire or fuel trim codes are there too, fix those first: they often cause this one.
- Inspect the parts involved: boost pressure sensor a, sensor wiring, charge air hoses.
- Work through the causes above from most to least likely, cheapest checks first.
- Clear the code and drive a full drive cycle to confirm the repair held.
Reading the code
- P
- Powertrain
- 0
- Generic (SAE) code
- 2
- Fuel and air metering (injector circuit)
- 37
- Specific fault
Questions drivers ask
Can I drive with code P0237?
Drive gently and only as far as you need to. The engine computer may limit power to protect the engine, so avoid highways and heavy traffic until it's fixed. If the check engine light starts flashing, pull over.
Will my car pass an emissions inspection with P0237?
Probably not in states that test vehicles with an OBD-II scan: an emissions-related code that keeps the check engine light on is usually an automatic fail. Rules differ by state and county, so check yours.
Can I fix P0237 myself?
Often yes, with an OBD-II scanner and basic tools. Difficulty: easy. Start with the cheapest checks before replacing expensive parts.
This page is general information, not a substitute for a professional diagnosis. Repair costs are rough estimates for parts and labor and vary by vehicle and region.