B2799 fault code: what it means

B2799: Engine immobiliser system malfunction on a Lexus: the immobiliser and engine ECU do not agree. Engine starts then stalls, or will not start.

Body · Costly if missed

Usual causes, most likely first

key not registered or failed key
immobiliser / smart key ECU fault
ECM swapped without matching

B2799 by make

Lexus

Engine immobiliser system malfunction on a Lexus: the immobiliser and engine ECU do not agree. Engine starts then stalls, or will not start.

Usual causes: key not registered or failed key; immobiliser / smart key ECU fault; ECM swapped without matching

Toyota

Engine immobiliser system malfunction (Toyota): the immobiliser and engine ECU are not agreeing. Engine starts and stalls or will not start.

Usual causes: key not registered or failed key transponder; immobiliser antenna/amplifier fault; ECM or immobiliser ECU swapped without matching

What the repair usually costs

Smart / proximity key supply and program (push-button start, sublet locksmith)NZ$430–NZ$960 · A$320–A$760
Smart key supply and program (European, sublet locksmith or dealer)NZ$580–NZ$1,540 · A$550–A$1,480

Not sure what B2799 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.