P0237
Turbocharger/Supercharger Boost Sensor A Circuit Low
When a vehicle powertrain module registers the fault code P0237, it points directly to an internal system malfunction identified as "Turbocharger/Supercharger Boost Sensor A Circuit Low". Operating your engine under this condition may degrade long-term fuel maps.
Driver's Summary
A P0237 fault code points directly to a problem with turbocharger/supercharger boost sensor a circuit low that the ECM has confirmed over multiple drive cycles. The most common signs are significant power loss, whistling noise, check engine light. Stop driving as soon as it is safe to do so. This fault can lead to expensive secondary damage if left unaddressed.
Symptoms
Significant power loss, whistling noise, check engine light
Common Causes
- Short to ground in boost sensor circuit
- Failed MAP/Boost sensor
- Massive boost leak (blown off charge pipe)
- Faulty turbocharger wastegate
How to Fix
- 1 Repair shorted sensor wire
- 2 Replace boost sensor
- 3 Reattach and tighten intercooler pipes
- 4 Inspect and repair wastegate
Technical Explanation
P0237 is stored after the control module confirms the fault over multiple ignition cycles, ruling out transient electrical noise as the cause. For injector-specific codes, the ECM monitors the injector control circuit voltage drop during each pulse; a shorted or open injector presents a characteristic resistance signature that differs measurably from a healthy unit. After two failed drive cycles, the code transitions from a pending to a confirmed DTC, and the PCM activates the MIL. Clearing the code without repairing the fault will result in re-illumination within one to two complete drive cycles.
Is It Safe to Drive?
With P0237 active, your engine or transmission is not operating within design parameters. Short-term driving may seem fine, but internal damage is accumulating — particularly to short to ground in boost sensor circuit.
Mechanic's Pro Tip
The most common mistake with P0237 is replacing the sensor without verifying the reference voltage and ground integrity first. Use a scan tool to monitor the sensor's live output; a truly failed sensor shows a stuck, flatlined reading — a sensor that fluctuates but reads slightly off usually indicates a wiring or vacuum issue, not a dead sensor. Always spray electrical contact cleaner on the connector pins before condemning the sensor.
Pipe reattachment: $50 - $100; Wastegate repair: $300 - $800