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

DTC P0546 EXHAUST GAS TEMPERATURE SENSOR CIRCUIT MALFUNCTION (HIGH INPUT)

DTC DETECTING CONDITION:

Detected when two consecutive driving cycles with fault occur.

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode and Inspection Mode .

WIRING DIAGRAM:

STEPCHECKYESNO

1.CHECK CURRENT DATA.

1) Start the engine and warm up engine until coolant temperature is higher than 75°C (167°F).

2) Using Subaru Select Monitor or general scan tool, read the data of exhaust gas temperature sensor 1 signal while keeping engine speed at 2,000 rpm.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to “READ CURRENT DATA FOR ENGINE”.

• General scan tool

For detailed operation procedures, refer to the general scan tool operation manual.

Does the exhaust gas temperature at catalyst inlet change from 40°C (104°F)?

Even if DTC is detected, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.

NOTE:

In this case, temporary poor contact of connector may be the cause.

2.CHECK POOR CONTACT.

Check for poor contact of ECM connector and exhaust gas temperature sensor 1 connector.

Is there poor contact in ECM connector or exhaust gas temperature sensor 1 connector?

Repair the poor contact of ECM connector or exhaust gas temperature sensor 1 connector.

3.CHECK HARNESS BETWEEN ECM AND EXHAUST GAS TEMPERATURE SENSOR 1 CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from the ECM and exhaust gas temperature sensor 1.

3) Measure the resistance of harness between ECM connector and exhaust gas temperature sensor 1 connector.

Connector & terminal

(B134) No. 54 — (E85) No. 1:

(B134) No. 72 — (E85) No. 2:

Is the resistance less than 1 Ω?

Repair the harness and connector.

NOTE:

In this case, repair the following item:

• Open circuit in harness between ECM connector and exhaust gas temperature sensor 1 connector

• Poor contact of coupling connector

4.CHECK HARNESS BETWEEN ECM AND EXHAUST GAS TEMPERATURE SENSOR 1 CONNECTOR.

1) Connect all connectors.

2) Turn the ignition switch to ON.

3) Measure the voltage between ECM connector and chassis ground.

Connector & terminal

(B134) No. 54 (+) — Chassis ground (−):

Is the voltage 5 V or more?

Repair the short circuit to power supply in harness between ECM connector and exhaust gas temperature sensor 1 connector.

Replace the exhaust gas temperature sensor 1.