DTC P0030 A/F/O2 Heater Control Circuit Bank 1 Sensor 1: Notes

DTC detecting condition:

Detected when two consecutive driving cycles with fault occur.

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Clear Memory Mode . and Inspection Mode Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Inspection Mode .
Use the check board when measuring the ECM terminal voltage and resistance.

Wiring diagram:

Engine Electrical System Ref. to WIRING SYSTEM>Engine Electrical System>WIRING DIAGRAM .

Fig 1: A/F/O2 Heater Control Circuit Bank 1 Sensor 1 - Wiring Diagram

G11270520

Courtesy of SUBARU OF AMERICA, INC.

CHECK HARNESS BETWEEN ECM AND FRONT OXYGEN (A/F) SENSOR CONNECTOR.
1. Start and warm up the engine.
2. Turn the ignition switch to OFF.
3. Disconnect the connectors from front oxygen (A/F) sensor.
4. Disconnect the connector from ECM.
5. Measure the resistance of harness between ECM and front oxygen (A/F) sensor connector.
  Connector & terminal
  
  (E158) No. 15 - (E24) No. 1:
  
  (E159) No. 9 - (E24) No. 2:
  
  (E158) No. 27 - (E24) No. 4:
  
  (E158) No. 39 - (E24) No. 5:
Is the resistance less than 1 Ω?
- Yes : Go to 2.
- No : Repair the open circuit of harness between ECM and front oxygen (A/F) sensor connector.
CHECK FRONT OXYGEN (A/F) SENSOR.
Measure the resistance between front oxygen (A/F) sensor terminals.

Terminals

No. 2 - No. 3:

Is the resistance 2 - 3 Ω?
- Yes : Go to 3.
- No : Replace the front oxygen (A/F) sensor. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>Front Oxygen (A/F) Sensor .
CHECK FOR POOR CONTACT.
Check for poor contact of ECM and front oxygen (A/F) sensor connector.

Is there poor contact of ECM or front oxygen (A/F) sensor connector?
- Yes : Repair the poor contact of ECM or front oxygen (A/F) sensor connector.
- No : Replace the front oxygen (A/F) sensor. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>Front Oxygen (A/F) Sensor .