P0238 code meaning
Turbocharger/Supercharger Boost Sensor A Circuit High
Powertrain system Generic code P02xx codes Check engine light
What P0238 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. With the ignition on and the engine stopped it must read the same as manifold and barometric pressure. P0238 means the signal voltage is above its upper limit: GM above 86 % of 5 V (about 372 kPa) for roughly 4 s with the warning light in the first trip, Ford above 4.88 V for 5 s, Saab's 1.6 turbo above 4.8 V. Causes are a signal shorted to 5 V or 12 V, an open sensor ground or – on GM modules with a pull-up input – an open signal wire. If several high codes appear at once, check the shared ground. 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.
P0238 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 1.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0238
- Check engine light on
- Clear loss of power, only base boost
- Boost reading implausible in a scan tool
Common causes of P0238
- Most likelySensor ground open, or signal wire open on a pulled-up input
- PossibleSignal shorted to 5 V or 12 V
- PossibleSensor faulty internally
- PossibleConnector corrosion or moisture at the ground
- Less likelyEngine module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Boost pressure sensor aSensor wiringCharge air hoses
What each part of P0238 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 2 | Area: fuel and air metering (injector circuit). |
| 38 | The exact fault in that area. |
What to do next
- Note P0238 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0238
What does P0238 mean?
P0238 means "Turbocharger/Supercharger Boost Sensor A Circuit High". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P0238?
Drive gently and only to a workshop. With P0238 the car can go into limp mode (reduced power) to protect itself.
Will P0238 fail an emissions test?
Yes, it can. P0238 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0238 to fix?
Difficulty: easy. A typical repair takes 0.3 to 1.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P0238 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.