P0209: Cylinder 9 Injector A Circuit/Open

What does P0209 mean?

P0209 reports an electrical fault, mainly an open circuit, in the injector circuit of cylinder 9. The engine module watches each injector output: GM flags an open circuit at an impedance of 200 kΩ or more – on direct injection and diesel engines in 10 of 20 or 5 of 10 samples and with the warning light in the first trip, on some port-injected engines only after two trips. Ford's port injection reads a fault bit from the driver chip that covers open, short to ground and short to voltage alike; Ford diesels report only the open circuit here and shorts as P0285/P0286. Cylinder 9 exists only on ten-cylinder engines; documented is Ford's 6.8 litre V10, whose check covers P0201 to P0210 with the warning light.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine light on
• Misfire and rough running, misfire code P0309
• Loss of power, rough idle
• Limp mode possible on diesel and direct injection

Common causes

• High Connector at the cylinder 9 injector loose, corroded or with a broken or pushed-back pin
• Medium Injector coil open
• Medium Wire between module and injector open or chafed (heat, rodents)
• Low Injector supply missing (fuse, relay) – then usually several cylinders at once
• Low Driver stage in the engine module faulty

Likelihood is a general estimate across vehicles; your make and model may differ.