P0236: Turbocharger/Supercharger Boost Sensor A Circuit Range/Performance

What it means

The boost pressure A signal stays within electrical limits but does not match expected values for the current operating point. Typical causes are leaking charge piping, a stuck wastegate, or sensor drift.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test
• The engine or gearbox may go into limp mode

How it works

Boost pressure sensor A measures pressure in the turbocharger or supercharger air system, and the control module checks whether its signal matches expected pressure as engine conditions change. P0236 sets when the signal remains electrically plausible but does not agree with the expected operating range, which can point to a leak, control problem, or sensor drift.

Common causes

Most likely first.

1. Charge air piping leaking
2. Wastegate stuck or seized
3. Sensor drift

Symptoms

• Check engine light on
• Significant power loss / limp mode
• Possible blue or black smoke from exhaust
• Whistling or hissing sound from intake

How to diagnose it

1. Record freeze-frame data and compare boost sensor A readings with engine load, throttle, and any other available pressure-sensor data.
2. Inspect charge-air pipes, couplings, and the intercooler for leaks, loose joints, or damage that could make actual boost differ from expected boost.
3. Check the wastegate or other boost-control mechanism for sticking or restricted movement.
4. Inspect sensor A and its connector and wiring for damage, then check its reference, ground, and signal against the wiring diagram.
5. If no leak or control fault is found, test sensor A’s response across operating conditions and compare it with the manufacturer’s specification.

Common fixes

• Tighten or replace a leaking charge-air pipe or coupling.
• Repair a sticking wastegate or boost-control mechanism.
• Repair damaged wiring or poor connections at boost sensor A.
• Replace sensor A if its readings drift or fail the specified response test.

Can I keep driving?

With reduced power, limp mode, smoke, or unusual intake noise, avoid hard acceleration and towing until the boost mismatch is diagnosed. A leak or control fault can worsen power loss and may place extra strain on the turbocharger if the vehicle is driven hard.