P1601 – ECM Communication Error (Toyota)

Description

The ECM detected a communication failure within the control network, affecting data exchange between modules.

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Symptoms

Check engine light on
Intermittent stalling
Unresponsive throttle
Communication errors
Failsafe mode

Causes

Faulty ECM
CAN bus wiring issues
Loose connectors
Low battery voltage
Corroded grounds

Diagnosis

Scan for network faults
Check CAN wiring
Inspect connectors
Measure battery voltage
Test ECM communication

Repair

Repair wiring
Clean connectors
Restore grounds
Replace ECM if required