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P1153 fault code: what it means

P1153: Subaru code: front air-fuel ratio sensor signal out of range (high) on bank 1. The ECU cannot trust the sensor for fuel control.

Engine and gearbox (powertrain) · Minor

Usual causes, most likely first

  1. ageing front A/F sensor
  2. A/F sensor wiring or connector fault
  3. vacuum or exhaust leak

P1153 by make

Subaru

Subaru code: front air-fuel ratio sensor signal out of range (high) on bank 1. The ECU cannot trust the sensor for fuel control.

Usual causes: ageing front A/F sensor; A/F sensor wiring or connector fault; vacuum or exhaust leak

Not sure what P1153 means on your car? Ask Credov.

Before you clear it

Write the code down or photograph the scanner first. A code that comes straight back after clearing points to a fault that is still there. A car whose codes were cleared just before you arrived may be hiding one: the scanner's readiness monitors show "not ready" for a while after codes are cleared.

Researched by Credov from manufacturer and workshop sources. A fault code points to where a fault may be; a workshop confirms it with a diagnosis. Browse all fault codes.