SAAB WIS ONLINE

DTC P0137 O2 SENSOR CIRCUIT LOW VOLTAGE (BANK 1 SENSOR 2)

DTC P0137 O 2 SENSOR CIRCUIT LOW VOLTAGE (BANK 1 SENSOR 2)

DTC DETECTING CONDITION:


• Two consecutive driving cycles with fault

• GENERAL DESCRIPTION

Important

After repair or replacement of faulty parts, conduct Clear Memory Mode and Inspection Mode .



WIRING DIAGRAM:


CHECK ANY OTHER DTC ON DISPLAY.

Is any other DTC displayed?

Yes

Using the List of Diagnostic Trouble Code (DTC), check the appropriate DTC.


No


CHECK REAR OXYGEN SENSOR DATA.

Warm-up the engine until engine coolant temperature is above 70°C (158°F), and keep the engine speed at 2,000 rpm to 3,000 rpm for 2 minutes.

Read the data of rear oxygen sensor signal using Vehicle Diagnostic Interface or OBD-II general scan tool.

Note
• Vehicle Diagnostic Interface

For detailed operation procedure, refer to the “READ CURRENT DATA SHOWN ON DISPLAY FOR ENGINE”.

• OBD-II general scan tool

For detailed operation procedures, refer to the OBD-II General Scan Tool Instruction Manual.


Does the value fluctuate?

Yes


No


CHECK REAR OXYGEN SENSOR DATA.

Read the data of rear oxygen sensor signal using Vehicle Diagnostic Interface or OBD-II general scan tool.

Is the voltage 0.2 — 0.4 V?

Yes


No

• Replace the rear oxygen sensor.


CHECK HARNESS BETWEEN ECM AND REAR OXYGEN SENSOR CONNECTOR.

Turn the ignition switch to OFF.

Disconnect the connectors from ECM and rear oxygen sensor.

Measure the resistance of harness between ECM and rear oxygen sensor connector.

Connector & terminal

(B135) No. 17 — (B19) No. 3:

Is the resistance more than 3 Ω?

Yes

Repair the open circuit in harness between ECM and rear oxygen sensor connector.


No


CHECK HARNESS BETWEEN REAR OXYGEN SENSOR AND ECM CONNECTOR.

Turn the ignition switch to OFF.

Disconnect the connector from rear oxygen sensor.

Turn the ignition switch to ON.

Measure the voltage between rear oxygen sensor harness connector and engine ground or chassis ground.

Connector & terminal

(B19) No. 3 (+) — Engine ground (−):

Is the voltage more than 0.2 V?

Yes

Replace the rear oxygen sensor.


No

• Repair the harness and connector.

•
Note

In this case, repair the following:

• Open circuit in harness between rear oxygen sensor and ECM connector

• Poor contact in rear oxygen sensor connector

• Poor contact in ECM connector



CHECK EXHAUST SYSTEM.

Check the exhaust system parts.

Note

Check the following items.

• Loose installation of portions

• Damage (crack, hole etc.) of parts

• Looseness and ill fitting of parts between front oxygen (A/F) sensor and rear oxygen sensor


Is there a fault in exhaust system?

Yes

Repair or replace the faulty parts.


No

Replace the rear oxygen sensor.