Guide To P042B OBD Error Code Solutions

<<See All OBD Codes

One of the most important pieces of emissions equipment on a vehicle is the catalytic converter. There are some exhaust gases which would pass through the catalytic converter which would then give rise to a chemical reaction. When this reaction has taken place, it would convert carbon monoxide, nitrogen oxides and hydrocarbon into harmless water as well as carbon dioxide.

Two oxygen sensors would then monitor the converter efficiency, one which is mounted upstream from the converter and the other one is mounted downstream. After comparing the oxygen sensor signals, then PCM can easily determine if the catalytic converter is working efficiently.

Want to learn something more about this fault code?

P042B code is set when the PCM would detect a range of performance problem in bank 1, catalyst temperature sensor 2 circuit. The trouble code P042B can be defined as Catalyst Temperature Sensor Circuit Range Performance.

What causes this problem with the Catalyst Temperature Sensor Circuit Range Performance (Bank 1 Sensor 2)?

• Defaults in the oxygen sensor
• Catalyst Temperature Sensor circuit might have bad electrical connection
• The PCM/PCM programming might be quirky
• The catalyst temperature sensor might have some defects
• Problems related to wiring
• The exhaust air/fuel mixture can be out of balance
• There can be opened or shorted catalyst temperature sensor harness

1. Powertrain Control Module - A faulty Powertrain Control Module can be troublesome. You can always rely on us as we have best auto parts for our customers.
2. Catalytic Converter - If everything is alright with PCM, then there is surely some defect in Catalytic Converter. Get it replaced before the situation gets worse.
3. Oxygen Sensor - P042B code can display due to some flaws in the Oxygen Sensor. So, it is very important to replace the Denso Oxygen Sensor with us at equitable prices.
4. Diagnostic Tool - Are you searching for Car Diagnostic Tools online? You can always rely on us as we have best Automotive Diagnostic Tools for our customers.
5. Air Fuel Ratio Sensor - Poor Air Fuel Ratio Sensor can cause a lot of difficulties, so why not get it replaced at time?
6. Exhaust System Parts - Are there some faults in your Exhaust System Parts? Don’t waste time and get them replaced or else P042B code can turn up.
7. Engine Control Module - OBD Code P042B can appear because of faulty boost Engine Control Module.

There could be countless symptoms which that would accompany with this fault code. Willing to know some common symptoms of OBD Trouble Code P042B? Your wish is our demand. Have a look at them below:

Common Symptoms

• The emissions can start rising
• There can be poor engine performance
• Illumination in the check engine light
• Decrease in the overall fuel economy

Looking out for some ways with the help of which you can correct this fault code? Then you have arrived at the correct place. We are here to help you out, so you must check out the steps mentioned below as follows:

• The defective wiring should be repaired or replaced properly
• A lot of problems can be caused due to programming error in the PCM, so you can always replace it
• Restore the quirky catalyst temperature sensor
• Inspect the electrical connection in the catalyst temperature sensor circuit

Don’t get tensed if you are still facing any of these issues as we care for our customers and that’s why we offer a good range of Oscilloscope, Obd2 Scanner, Car Scanner, Exhaust Catalyst and a lot more. We are sure that now all your issues would be resolved.

It is essential to diagnose this fault code. Here are some steps which a mechanic should follow for diagnosing the problem that triggered a P042B code to be stored:

• Visually inspect the downstream oxygen sensor and the corresponding wiring. Look for loose connections, damaged wiring, etc.
• You should also inspect for exhaust leaks both visually as well as audibly. A false oxygen sensor code can be cause due to an exhaust leak. If damage is found, repair as necessary, clear the code and see if it returns.
• The next step would be to check for technical service bulletins regarding the issue. If nothing is found, you will need to move forward to step by step diagnosis of the system. The following is a generalized procedure, as testing for this code varies between vehicles. To accurately test the system, you can always refer to a vehicle make/model specific diagnostic flow chart.

Check for other DTCs

Oxygen sensor codes can often be set because of engine performance problems that cause an out of balance air/fuel mixture. If there are other DTCs stored, you can always address those first

before proceeding with oxygen sensor diagnosis.

Check Sensor Operation

This is best done using a scan tool, or better yet, an oscilloscope. Since most individuals don't have access to a scope, so we will cover oxygen sensor diagnosis using a scan tool. Connect the scan tool to the OBD port under the dash. Turn the scan tool on and choose the Bank 1 Sensor 2 voltage parameter from the data list. Bring the engine up to operating temperature and view the sensor operation on the scan tool in graph mode.

The sensor should have a steady 0.45 volt reading with only very small fluctuations. If it is not responding correctly then it should be replaced.

Check the circuit

Oxygen sensors produce their own voltage signal which is sent back to the PCM. Before proceeding, you can always consult the factory wiring diagrams to determine which wires are which. To check for continuity between the sensor and PCM, turn the ignition key to the "off" position and disconnect the O2 sensor connector.

Connect a digital multimeter set to ohms with the ignition off between the O2 sensor signal terminal on the PCM and the signal wire. If the meter reads out of limits (OL) there is an open circuit between the PCM and sensor that will need to be located and repaired. If the meter reads a numeric value, it means that there is continuity. Next, you'll want to check the ground side of the circuit. To do this, turn the ignition key to the "off" position and disconnect the O2 sensor connector. Connect a digital multimeter set to ohms (with the ignition off) between the O2 sensor connector ground terminal (harness side) and chassis ground. If the meter reads out of limits (OL) there is an open circuit on the ground side of the circuit that will need to be located and repaired. If the meter reads a numeric value, there is continuity to ground. Finally, you should check that the PCM is processing the O2 sensor signal properly.

To do this, leave all the connectors attached and insert a back-probe meter lead into the signal terminal at the PCM. Set the digital multimeter to the DC volts setting. With the engine warmed up, compare voltage reading on the meter to that on the scan tool. If the two do no match, the PCM is likely faulty and there is a need to reprogram the powertrain control module.

Common Mistakes When Diagnosing The P042B Code

• Catalytic converter temperature sensor might start failing
• Quirks in the powertrain control module
• Problems related to wiring