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P1792

Barometer Pressure Circuit.

  • Mazda
  • Powertrain
  • Manufacturer code
  • Medium severity

How this code is built

P
SystemPowertrain
1
Defined byThe manufacturer
7
AreaTransmission
92
FaultThe specific fault in that area

What it means

On a Mazda, P1792 means the engine control unit has detected a fault in the barometric pressure circuit. It compares the barometric pressure signal with expected values, such as manifold pressure at key-on or engine off, and sets the code when the signal is out of range, implausible or electrically faulty. Without a reliable altitude reading the ECU may miscalculate fuelling and air load.

Symptoms

  • Check engine light on
  • Poor performance or hesitation, especially under load
  • Rich or lean running, or rough idle
  • Hard starting or an unstable idle at altitude or after a change in weather
  • Poorer fuel economy
  • Occasional stalling or surging

Possible causes

  • Faulty barometric pressure sensor, or MAP sensor where the barometric reading is taken from itlikely
  • Damaged wiring, poor connector contact or corrosion in the sensor's supply, ground or signal circuitlikely
  • Blocked, split or disconnected vacuum or pressure hose to the sensor (on models where one is fitted)possible
  • Sensor reference voltage or ground fault caused by another faulty sensor on the same circuitpossible
  • Restricted air intake or air filter issue affecting pressure readingsrare
  • Faulty engine control unitrare

How to diagnose

  1. Read all stored and pending codes and note the freeze frame data, looking for other sensor circuit codes that point to a shared supply or ground fault
  2. Check live data for barometric pressure with the ignition on and engine off. It should match local atmospheric pressure, roughly 100 kPa near sea level, and agree with the manifold pressure reading
  3. Visually inspect the sensor, its connector, wiring and any vacuum hoses for damage, chafing, corrosion, splits or blockages
  4. Check where the sensor is located on this model, as barometric pressure may be measured by a separate sensor or by the manifold pressure sensor depending on engine and year
  5. Measure the sensor supply voltage, ground and signal at the connector against the manufacturer's specification
  6. Wiggle-test the harness and connector with live data displayed to look for intermittent dropouts
  7. Check the wiring for continuity and for shorts to ground or voltage between the sensor and the control unit
  8. Compare the sensor reading against a known good reference gauge or another vehicle before condemning the sensor or control unit

How to fix

  • Replace the barometric pressure sensor, or the combined MAP sensor, if its readings are out of range or it fails the electrical tests
  • Repair or replace damaged wiring and clean or renew corroded connector terminals
  • Clear, refit or replace blocked, split or disconnected vacuum hoses
  • Rectify any shared reference voltage or ground fault, including faulty sensors that pull the supply down
  • Clean or replace a restricted air filter or intake component if it affects the readings
  • Have the control unit tested and replaced or reprogrammed only if all inputs and wiring are proven good

Can I keep driving?

Medium severity

The car can usually be driven carefully for a short time, but fuelling may be inaccurate, causing poor running and higher fuel use. Get it diagnosed soon, and stop if it stalls or runs very badly.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.

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