DTC 27 ODS Communication Error: DTC Detecting Condition

WARNING: This page is about a different car, the 2011 Subaru Tribeca. However, it is still accessible from the selected car via links, so may be relevant.

Communication to the occupant detection control module is faulty.
Airbag rear harness circuit is open, shorted, shorted to ground or shorted to power supply.
Occupant detection harness (seat harness) is faulty.
Occupant detection system is faulty.
Airbag control module is faulty.

CAUTION: Refer to CAUTION , General Description.

Step	Check	Yes	No
1 CHECK POOR CONTACT OF CONNECTORS. Check for poor contact of the connectors between the airbag control module and the occupant detection control module.	Is there poor contact?	Reconnect the connector. If defective is not improved, replace the airbag rear harness along with the body harness or the occupant detection harness (seat harness).	Go to step 2 .
2 CHECK AIRBAG HARNESS. Turn the ignition switch to OFF, disconnect the battery ground cable, and wait for 60 seconds or more. Disconnect the connectors (AB6, AB17, AB18) from airbag control module. Disconnect the connectors (AB59) and (AB53) under the passenger's seat. Connect the test harness AG connector (1AG) to the connectors (AB6, AB17, AB18). Connect the connector (1AB) in the test harness AB to the connector (AB53). Measure the resistance between connector (6AG) in the test harness AG and connector (2AB) in the test harness AB. Connector & terminal (6AG) No. 9 - (2AB) No. 1: (6AG) No. 11 - (2AB) No. 2:	Is the resistance less than 10 Ω?	Go to step 3 .	Replace the airbag rear harness along with body harness.
3 CHECK AIRBAG HARNESS. Measure the resistance between connector (6AG) in the test harness AG and chassis ground, and between connector terminals (6AG). Connector & terminal (6AG) No. 9 - Chassis ground: (6AG) No. 9 - (6AG) No. 11:	Is the resistance less than 10 Ω?	Go to step 4 .	Replace the airbag rear harness along with body harness.
4 CHECK AIRBAG HARNESS. Turn the ignition switch to ON. Measure the voltage between connector (2AB) in the test harness AB and chassis ground. Connector & terminal (2AB) No. 3 (+) - Chassis ground (-):	Is the voltage 9 V or more?	Replace the occupant detection harness (seat harness). If defective is not improved, replace the occupant detection system (seat cushion & frame assembly), and then the airbag control module in this order.	Check the battery voltage and fuse. If there is no fault, replace the airbag rear harness along with body harness or replace the body harness.