An oxygen sensor does not work until it reaches 570 °F, so it carries its own heater — and the heater is what fails first. Why this does not always mean replacing the sensor.
The most common code after misfires. It means the module is adding fuel and still cannot keep up. Seven causes in order of probability, and how to narrow the search using fuel trims alone.
The mirror image of P0171: too much fuel, and the module cannot remove enough of it. The causes, why the catalyst suffers, and how a rich mixture kills an engine through its oil.
These codes name a specific cylinder, which is why they get read as "the injector died". In fact the module is complaining about an electrical circuit, and the injector is only one of three elements in it.
The car cranks and never catches. No spark, no fuel, and possibly no codes stored. The sensor without whose signal the control module will not even begin to try.
The engine will not start first time, occasionally stalls and restarts immediately. That is the camshaft sensor signature: it does not stop the engine permanently, it makes it unpredictable.
The speedometer sits at zero, and with it the cruise control, the power steering assist, and the transmission all misbehave. Why one speed signal is needed by almost every module at once.
Idle swings between 500 and 1200 RPM and the car stalls at lights. The universal advice is to clean the throttle body. When that works, and when it merely postpones the real cause.
New battery, alternator charging, and the car still will not start in the morning. Something is refusing to sleep. How to narrow the search through diagnostics, and where the line is beyond which you need a multimeter.
Hydraulic assist gets heavy from fluid level and belts. Electric assist gets heavy from voltage, the angle sensor, and the speed signal. Both designs, and why on modern cars the culprit sits somewhere else entirely.
The Duster is bought for simplicity, and that simplicity pays off — most faults here fall into the "find it and replace it yourself" category. Broken down by engine version, plus what four-wheel-drive owners should check.
A pump that only runs on a cold start, and only for a minute and a half. It sits idle the rest of the time — which is precisely why it corrodes, seizes, and eventually produces a code that fails your emissions test.