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P1621 fault code: what it means

P1621: Immobiliser control module to ECM communication fault. Engine may not start.

Engine and gearbox (powertrain) · Costly if missed

Usual causes, most likely first

  1. wiring or fuse fault
  2. immobiliser control module
  3. ECM

P1621 by make

Suzuki

Immobiliser control module to ECM communication fault. Engine may not start.

Usual causes: wiring or fuse fault; immobiliser control module; ECM

Not sure what P1621 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.