Diagnostic Trouble Code (DTC) P0137

Rear Heated Oxygen Sensor Low Voltage



                                                                                Features of the Circuit

  • A voltage approximately of 450mm volts is generated by the ECM between the ECM terminals 44 and 13.
  • If the Exhaust Is RICH:    The Heated oxygen (O2) sensor is devised to alter the voltage between a range of about 1volt.
  • If the Exhaust Is POOR:  The Heated oxygen (O2) sensor is devised to alter the voltage between a range of about 100mm volt.
  • The Heated O2 sensor acts quite like an open circuit and does not generate any voltage when it is below 360°C(600°F).
  • An "open loop" operation is created by an open O2 sensor circuit or a cold O2 sensor.



Conditions for Setting the DTC



When  1) The engine controls system is in closed loop.

When  1)  The engine controls system is in full fuel cut off.

           2)   Engine speed is less than 6,000rpm

            2) Engine speed is less than 6,000rpm

           3)     The oxygen sensor voltage is  below 0.07V for at least 40seconds     

            3)   The oxygen sensor voltage is between 0.352 and 0.499 at least 10 seconds  

           4)   DTCs P0107, P0108, P0117, P0118, P0122, P0123, P0335, P0336, P0341, P0342, P0400, P0404, P0405, P0406 are NOT SET.


     4)  DTCs P0107, P0108 and P0141 are NOT SET.







Task Boosted When DTC sets

When Does DTC clear?

1) It will be found that the Malfunction Indicator Lamp (MIL) is glowing.

1)   The MIL will stop work after four repetitive ignition cycles where the diagnostic functions flawlessly.


2) The ECM is devised to record operating conditions at the time the diagnostic fails which will be stored in the Freeze Frame and Failure Records will be boosted.


2)  A history DTC will clear after 40 consecutive warm-up cycles without a fault

3) A history DTC is stored.


3)  The Scan Tool can be made use of in order to clear all DTCs

4) The coolant fan will turn ON.


4) Disconnecting the ECM battery feed for more than 10 seconds






Diagnostic Assistance:

  • Here the circuit is devised so that the normal scan tool voltage fluctuates between 0.1 volts and 0.9 volts while it is in closed loop.
  • It is advised that you inspect the oxygen (O2) sensor wire where the  O2 sensor could  be placed inaccurately and contacting the exhaust manifold.
  • Also look for an intermittent ground in the wire found between the O2 sensor and the ECM.
  • Execute an injector balance test to ensure that a restricted fuel injector is not responsible for a lean condition.
  • If any vacuum of crankcase leaks exists then  a lean running condition will prevail.
  • Outside air may be sucked into the exhaust and past the sensor if an exhaust manifold gasket leak of a cracked exhaust is found to exist.