ENGINE (DIAGNOSTICS)(H4DOTC) > Diagnostic Procedure with Diagnostic Trouble Code (DTC)

DTC DETECTING CONDITION:

Detected when two consecutive driving cycles with fault occur.

TROUBLE SYMPTOM:

• Radiator fan does not operate properly.

• Overheating

CAUTION:

After repairing or replacing the defective part, perform the Clear Memory Mode and Inspection Mode .

WIRING DIAGRAM:

STEP	CHECK	YES	NO
1.CHECK OUTPUT SIGNAL OF ECM. 1) Turn the ignition switch to OFF. 2) Connect the test mode connector. 3) Turn the ignition switch to ON. 4) While operating the radiator fan relay, measure voltage between ECM and chassis ground. NOTE: The radiator fan relay can be operated using the Subaru Select Monitor. Regarding the procedures, refer to “Compulsory Valve Operation Check Mode”. Connector & terminal (B136) No. 29 (+) — Chassis ground (−): (B136) No. 18 (+) — Chassis ground (−):	Does the voltage change between 0 — 10 V?	Even if the malfunction indicator light illuminates, the circuit has returned to a normal condition at this time. In this case, repair the poor contact in ECM connector.
2.CHECK SHORT CIRCUIT IN RADIATOR FAN RELAY CONTROL CIRCUIT. 1) Turn the ignition switch to OFF. 2) Remove the fan relay 1, fan relay 2 and fan mode relay. 3) Disconnect the test mode connector. 4) Turn the ignition switch to ON. 5) Measure the voltage between ECM and chassis ground. Connector & terminal (B136) No. 29 (+) — Chassis ground (−): (B136) No. 18 (+) — Chassis ground (−):	Is the voltage 10 V or more?	Repair the battery short circuit in radiator fan relay control circuit.
3.CHECK FAN RELAY. 1) Turn the ignition switch to OFF. 2) Remove the fan relay. 3) Measure the resistance between fan relay terminals. Terminals No. 30 — No. 31: (fan relay 1) No. 28 — No. 29: (fan relay 2)	Is the resistance less than 1 Ω?	Replace the fan relay.
4.CHECK FAN MODE RELAY. 1) Remove the fan mode relay. 2) Measure the resistance between fan mode relay terminals. Terminals No. 8 — No. 9: (fan mode relay)	Is the resistance less than 1 Ω?	Replace the fan mode relay.
5.CHECK POOR CONTACT. Check poor contact of ECM connector.	Is there poor contact in ECM connector?	Repair the poor contact of ECM connector.	Replace the ECM.