P1605 FIAT Automatic Transmission Communication

Possible causes

– Weak battery
– Faulty Transmission Control Module (TCM)
– Harness is open or shorted between (TCM) and Engine Control Module (ECM)
– Poor circuit electrical connection between (TCM) and (ECM)

What about the obd code?

Malfunction is detected when an incorrect signal from Transmission control module (TCM) is sent to Engine Control Module (ECM).

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P1605 FIAT Description

The malfunction information related to Automatic Transmission is transferred through the line circuit from Transmission control module (TCM) to Engine Control Module (ECM).