Question

I/M Status shows Htd.Catalyst n/a on1997 Dodge Grand Caravan 3.3 Litre when taken by OBD ll Scanner.

Answer 1

if you have a P0306 which is a misfire the I/M might not complete. 

check/replace the spark, coil/wire, injector and so on

P0306 Dodge - Cylinder 6 Misfire Fault Detected

Possible causes

- Faulty spark plug 6

- Clogged or faulty fuel injector 6

- Faulty ignition coil 6

- Fuel injector 6 harness is open or shorted

- Fuel injector 6 circuit poor electrical connection

- Ignition coil 6 harness is open or shorted

- Ignition coil 6 circuit poor electrical connection

- Insufficient cylinder 6 compression

- Incorrect fuel pressure

- Intake air leak