Fault code 258400 exhaust gas temperature sensor upstream of the oxidation catalytic converter signal to high indicate problem towards exhaust gas temperature sensor which is located at before catalytic converter. Exhaust gas temperature sensor is use to monitor temperature of exhaust gas and send this signal to engine control module. Engine control module monitor this signal and according to this manage firing order of fuel injection and so many other things as well. This fault code could be store in engine control module due to many reasons but the main reason behind this fault is usually block dpf (diesel particulate filter). When diesel participate filter get block heavily it does not pass exhaust gas properly due to this reason most of the fault 258400 exhaust gas temperature sensor upstream of the oxidation catalytic converter signal to high store in control module.
Causes of 258400 exhaust gas temperature sensor:
there are many reasons due to which this fault code could be store in engine control module and they are listed below.
- Block DPF (diesel participate filter).
- Leak exhaust gas pipe.
- Faulty exhaust gas temperature sensor.
- Miss firing at combustion engine.
- Wrong signal from air mass sensor Or manifold absolute pressure sensor.
Symptoms of 258400 exhaust gas temperature sensor:
Most of the time when this fault code store in engine control module. There will be the problem of engine power at high speed.
- Pickup issue at high speed.
- White smoke from exhaust.
- Engine will start missing.
- Fault code will store in engine control module.
How to trouble shoot:
When you find this fault code store in engine control module. You need to work on this fault code very carefully. Because this fault code could be store in control module due to multiple faulty sensor like air mass sensor, manifold pressure sensor, exhaust gas temperature sensor etc.
In this situation you need to check all the sensor one by one to solve this kind of problem. First thing you need to do is hook up scan tool, check reading of exhaust gas temperature sensor, if reading is fluctuating or not. If reading is fluctuating and changing according to the acceleration. Than you can consider it that there could be some other problem because reading of the sensor is fluctuating. To confirm this that sensor is giving proper reading to engine control module or not compare that reading according to required reading.
If it does match with required reading than it not a fault code of exhaust gas temperature sensor. But it showing reading and not matching with the require reading than it means that sensor is proving proper signal to engine control module due to which this fault code is store in control module. When this kind of problem is seen it is better to replace that sensor and then check fault code. If fault code is gone than it’s good but if still it does not. Than it means that there is some other problem due to which this fault code is store in control module.
The second thing that which can create this fault code is block DPF (diesel particulate filter). When diesel particulate filter get block, it stop exhaust gas passing through exhaust gas. Due to which very heavy amount of exhaust gas get return from there. In result which exhaust gas temperature sensor sense this return gas and give signal of about it to engine control module.
When engine control module receive this signal from exhaust gas temperature sensor it stop or start injecting fuel into combustion chamber in very heavy amount due to which either missing problem in engine will be there or white smoke will come out from exhaust pipe. Due to unburned fuel in combustion chamber white smoke comes out. To solve this problem you need to clean DPF (diesel particulate filter). This could be done by either with the help of scan tool, or clean it by removing it outside from engine with the help of cleaning agent.
The other thing that can be the reason behind this fault code is electrical fault in the system. Like this fault code could be store in control module due to failure of air mass sensor, failure or manifold sensor. Check if all these fault code is also store in engine control module or not. If they are also store in control module than it might be possible that there is a problem with air mass sensor. Check problem at air mass sensor, its wiring harness, loose connection at connector, leak air mass sensor pipe. Check all these things one by one so that you can find the solution of this problem.
Common mistake while solving this fault code:
Most of the time when mechanic start diagnosing and found this fault code store in control module. They start working on Exhaust gas recirculation system. As this fault code indicate problem toward exhaust gas recirculation system. But this is not the actual problem of exhaust gas system.
Follow all the above direction so that it can make easy to understand the actual problem. Help you to find out the reason behind this fault code as easy as possible.
Solution:
Replace faulty exhaust gas temperature sensor.
Repair damage wiring harness of the sensor.
Clean block diesel particulate filter.
Replace faulty air mass sensor.
Repair damage wiring harness of the air mass sensor.
Replace blow fuse of sensor.
Repair or replace faulty engine control module.