P1133 fault code: what it means

P1133: Mixture adaptation, lower load range, bank 2: the DME cannot make the mixture rich enough (sees too much air).

Engine and gearbox (powertrain) · Minor

Usual causes, most likely first

intake air leak
faulty MAF signal
low fuel pressure or weak pump
fouled injectors

P1133 by make

Porsche

Mixture adaptation, lower load range, bank 2: the DME cannot make the mixture rich enough (sees too much air).

Usual causes: intake air leak; faulty MAF signal; low fuel pressure or weak pump; fouled injectors

Toyota

A/F sensor circuit response, bank 1 sensor 1 (older Toyota code): the front air-fuel sensor is too slow.

Usual causes: aged or contaminated A/F sensor; exhaust leak before the sensor

What the repair usually costs

High-pressure fuel pump (GDI petrol or common-rail diesel)NZ$1,140–NZ$4,280 · A$1,060–A$3,800

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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.