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
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CASE 1 |
CASE 2 |
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When 1) The engine controls system is in closed loop. |
When 1) The engine controls system is in full fuel cut off. |
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2) Engine speed is less than 6,000rpm |
2) Engine speed is less than 6,000rpm |
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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 |
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4) DTCs P0107, P0108, P0117, P0118, P0122, P0123, P0335, P0336, P0341, P0342, P0400, P0404, P0405, P0406 are NOT SET.
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4) DTCs P0107, P0108 and P0141 are NOT SET.
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Task Boosted When DTC sets |
When Does DTC clear? |
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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.
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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.
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2) A history DTC will clear after 40 consecutive warm-up cycles without a fault |
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3) A history DTC is stored.
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3) The Scan Tool can be made use of in order to clear all DTCs |
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4) The coolant fan will turn ON.
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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.