P1621

DTC P1621
Communications with the security ECM has not happened within the expected time (Driving Cycle A)

Possible causes by suggested order of priority:
- Connectors C1017, C225.
- Circuit integrity C1017/26 (B) - C225/15 (B).
- Alarm ECU.
- ECM.

Connectors C1017, C225.
- Check for connector not correctly latched, backed out pins, damaged pins, corroded pins

Circuit integrity C1017/26 (B) - C225/15 (B).
- Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers

Alarm ECU.
- No detail available for this fault

ECM.
- No detail available for this fault