why do nox sensors fail?
605552
NOx sensors monitor the level of nitrogen oxide being emitted by a diesel vehicle to ensure compliance with emissions regulations. ... Common causes of failure include soot buildup on the sensor, ECU water intrusion, and/or damage to the cable, which will cause the check engine light to illuminate.
1411443
An air/fuel sensor can read a much wider and leaner range of fuel mixtures than a conventional O2 sensor. That's why they're also called “wideband” O2 sensors. Another difference is that A/F sensors don't produce a voltage signal that suddenly changes on either side of Lambda when the air/fuel goes rich or lean.
1275076
O2 sensor "isolators" DO NOT WORK! They do exactly opposite of what is claimed. The O2 sensor output would have to be RAISED in voltage to lean out the mix. Taking the sensor out of the exhaust stream lowers the temperature, which LOWERS the voltage and causes the ECU to richen up the fuel air mix ratio!
903347
No - IAC (Intake Air Temperature) sensor / circuit malfunction has no affect single cylinder misfire. The IAT sensor wire connector often gets disconnected inadvertently when other engine services are being performed and just needs to be re-connected..
941815
Can you clean an oxygen sensor? No, despite what you might have heard or read, such sensors should be replaced when they become faulty.
145503
Yes, it should be an MOT failure. It'll be classed as part of the ESC (Electronic Stability Control) system. Does it put on the traction control and ABS lights, or just the traction control? ... However, since the same sensors are used for the ABS and ESP, a fault in one should trigger a fault in the other.
1241667
If the EGR valve is clogged or completely blocked off it can longer re-burn harmful emissions in the combustion chamber. The NOx emissions will flow unregulated through the combustion chamber and out of the exhaust pipe. The excessive NOx emissions will show up during a smog test and cause a failure.
941669
Intermittent ignition coil failures are tough to diagnose because the windings are heat sensitive. This can cause a coil to pass shop tests but fail under loads. ... Most technicians working on ignition coils use a computer based digital oscilloscope to measure the waveforms produced.
1242298
You can get a MAF signal too high code as a result of overboost and a boost leak. You're vacuuming too much air past the MAF since the leak is causing the ECU to increase N75 duty cycle to get the boost where it belongs.
394205
Check the evaporator coil and remove the TXV's sensing bulb from the suction line. Check the subcooling, superheat and pressures again. If there's no change, that's a further indication of a TXV problem. Another test is to put the sensing bulb in ice water and checking the pressures superheat, and subcooling again.
76421
Carbon monoxide alarms ALONE do NOT detect propane/methane/natural gas leaks. Carbon monoxide sensors detect ONLY carbon monoxide, not raw fuel or fumes. It does not take striking a match to cause a gas explosion or fire. ... Each gas appliance needs its own gas detector.
237650
Tire pressure sensors also can fail as a result of corrosion on or inside the valve stem. This has been a serious problem with some makes (notably Toyota) and has resulted in valve stems cracking or breaking off and making a tire to suddenly go flat (just the sort of thing TPMS sensors were supposed to prevent!).
1200263
A defective, dirty or corroded wheel speed sensor, or a fault in the wiring that connects it, will keep the proper information from getting to the TCS computer, preventing the traction control on that wheel from working. This can cause the system to stop functioning, illuminating the TCS warning light.
600842
Look at the sensors, there should be a light on each sensor. If not one of them has probably been bumped or kicked. They should both be green. Just eye them up to look at each other until the lights both come on strong and steady.
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3. Rough engine idle and misfires. ... Since the oxygen sensor output helps control engine timing, combustion intervals, and the air to fuel ratio, a bad sensor can disrupt these engine functions, causing a rough or irregular engine idle.
1070897
Common reasons for this to happen: Blown fuse: Like many electrical units in your car, the ventilation system relies on a fuse for overcurrent protection. If the ventilation system's fuse blows, then the circuit will stop working, and there will be no power for the vents. Bad relay: A bad relay can also be responsible.
1135608
The top reasons for fuel pump failure are contamination, overheating, and the gears in the the fuel pump wearing out over time. Rust, debris, and dirt are three common particles that can somehow enter the gas tank and be fed towards or through the intank fuel filter and possibly into the fuel pump.