Skip to content
GTECH Calibration
Portal

P1195

EGR Boost Sensor Circuit.

  • Mazda
  • Powertrain
  • Manufacturer code
  • Medium severity

How this code is built

P
SystemPowertrain
1
Defined byThe manufacturer
1
AreaFuel and air metering
95
FaultThe specific fault in that area

What it means

On Mazda, P1195 means the engine control unit has found a fault in the EGR boost sensor circuit. This sensor measures pressure used to monitor or control exhaust gas recirculation flow. The code sets when the signal voltage is out of its expected range or does not agree with other readings such as barometric or manifold pressure. The exact sensor location and test values depend on the model and engine.

Symptoms

  • Engine warning light on
  • Slight loss of power or flat response under load
  • Rough or unstable idle
  • Poor fuel economy
  • Possible increase in exhaust smoke on diesel engines
  • Failed emissions test

Possible causes

  • Faulty EGR boost (pressure) sensorlikely
  • Damaged, chafed or corroded wiring to the sensor (open circuit, short to earth or short to supply)likely
  • Poor connection at the sensor or control unit connector (corrosion, loose or bent terminals)likely
  • Blocked, split or disconnected vacuum or pressure hose to the sensorpossible
  • Heavy carbon build-up in the EGR passages or sensor port affecting readingspossible
  • Fault in the sensor supply or reference voltage circuitrare
  • Faulty engine control unitrare

How to diagnose

  1. Read all stored and pending codes and note the freeze frame data (engine load, speed, temperature) from when the fault set.
  2. Check for related codes covering EGR, manifold pressure or sensor supply voltage, as these point to a shared wiring fault.
  3. Visually inspect the sensor, its connector, wiring and any hoses for damage, chafing, heat damage, corrosion or loose fit.
  4. Check the sensor hose or port for blockage, splits or carbon build-up.
  5. View live sensor data with the ignition on and engine off, and compare it with barometric pressure; it should read plausibly and steadily.
  6. Check the sensor supply, earth and signal wires with a multimeter against the manufacturer's wiring diagram, including continuity and shorts.
  7. Compare the sensor reading while the engine runs and under load with expected values for that model.
  8. Clear the code after repair and road test to confirm it does not return.

How to fix

  • Replace the EGR boost sensor if it fails the signal checks.
  • Repair or replace damaged wiring and clean or repair corroded or loose connector terminals.
  • Replace blocked, split or perforated hoses and clear any blockage at the sensor port.
  • Clean or repair a carbon-fouled EGR passage following the manufacturer's procedure.
  • Have the control unit tested, and replaced or reprogrammed per manufacturer guidance, only if the wiring and sensor are proven good.

Can I keep driving?

Medium severity

The car can usually be driven for a short time, but book it in soon as EGR control may be impaired, which can affect emissions, economy and running quality. If it runs badly or loses power, limit driving until it is checked.

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

This code for other makes

Nearby codes