Diagnostic guide for P0137

Diagnostic Guide for P0137 - O2 Sensor Circuit Low Voltage Bank 1 Sensor 2

The P0137 code indicates a low voltage issue with the rear heated oxygen sensor on Bank 1. This guide aims to help diagnose the underlying cause of the low voltage signal, which can affect fuel efficiency and emissions.

✓

Difficulty

Intermediate

⏱

Estimated Time

30-60 Minutes

Estimated Diagnostic Cost

$0-$100

Typical shop charge to perform this diagnostic process. Repair parts and labor are not included.

⚙

Tools Needed

OBDII scanner, multimeter, wiring diagram, basic hand tools

Safety Notes

Ensure the engine is cool before working on the exhaust system. Use caution when lifting the vehicle and working under it. Wear safety glasses and gloves.

Step 1

Check for Diagnostic Trouble Codes (DTCs)

Instruction Connect an OBDII scanner to the vehicle's diagnostic port and retrieve any stored codes.

Expected result The scanner should display the P0137 code along with any other related codes.

If Pass If P0137 is the only code present, proceed to the next step.

If Fail If other codes are present, investigate those first as they may be related to the oxygen sensor issue.

Ask Coddy about this step

Coddy can help with this step only. Tell me what you tested or what result you got.

Step 2

Inspect the O2 Sensor Wiring and Connector

Instruction Visually inspect the wiring and connector for the rear heated oxygen sensor on Bank 1 for any signs of damage, corrosion, or loose connections.

Expected result Wiring and connector should be intact with no visible damage.

If Pass If the wiring and connector are in good condition, proceed to test the sensor voltage.

If Fail If damage is found, repair or replace the wiring or connector as necessary.

Ask Coddy about this step

Coddy can help with this step only. Tell me what you tested or what result you got.

Step 3

Test the O2 Sensor Voltage

Instruction Using a multimeter, measure the voltage output of the rear heated oxygen sensor while the engine is running.

Expected result The voltage should fluctuate between 0-1,000 mV as the engine runs.

If Pass If the voltage is fluctuating normally, the sensor may be functioning correctly, and further investigation into other causes is needed.

If Fail If the voltage is consistently below 50 mV, the sensor may be faulty or there may be an issue with the circuit.

Ask Coddy about this step

Coddy can help with this step only. Tell me what you tested or what result you got.

Step 4

Check for Ground Issues

Instruction With the multimeter, check the ground connection for the O2 sensor to ensure it has a good ground.

Expected result The ground should show continuity with minimal resistance.

If Pass If the ground is good, the issue may lie within the sensor itself or the ECM.

If Fail If there is high resistance or no continuity, repair the ground connection.

Ask Coddy about this step

Coddy can help with this step only. Tell me what you tested or what result you got.

Step 5

Test for Short Circuits

Instruction Check the O2 sensor circuit for any shorts to ground using the multimeter.

Expected result There should be no continuity between the signal wire and ground.

If Pass If no shorts are found, the sensor may need to be replaced.

If Fail If a short is detected, inspect the wiring for damage and repair as necessary.

Ask Coddy about this step

Coddy can help with this step only. Tell me what you tested or what result you got.

Step 6

Evaluate Fuel System and Exhaust Integrity

Instruction Check for any exhaust leaks or fuel system issues that could affect the O2 sensor's readings.

Expected result The exhaust system should be leak-free, and fuel pressure should be within specifications.

If Pass If everything checks out, consider replacing the O2 sensor as the final step.

If Fail If leaks or fuel issues are found, address those problems before replacing the sensor.

Ask Coddy about this step

Coddy can help with this step only. Tell me what you tested or what result you got.