Catalytic converters must be warm before they can work properly. On a cold start the PCM provides a rich mixture to keep the cold engine running.
All that extra fuel goes into the catalytic converter. But the exhaust isn't very hot, because, ah, the engine is pretty cold. GM has employed several strategies to fire up the catalytic converter quicker and reduce cold start emissions. One way is to use a secondary air pump that pumps outside air directly into the catalytic converter.
One example of this would be when an automatic vehicle in placed in gear. To prevent the added drag from the torque converter and transmission from reducing the idling speed, the PCM will command the idle control valve to allow more air to enter the engine, while at the same time, adjusting the injector pulse width to inject more fuel to suit the increased amount of air. Note that the idle air control valve is closed by the PCM when the throttle plate is opened to prevent excess air from entering the engine.
Difficulty Level (Expert)
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Repair Time (35 Min.)
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| Cost Prediction : $ 40-75 |
If your transmission fluid temperature sensor circuit intermittent check engine light is illuminated, it's best to take it in for diagnostic testing, which can feel like a hassle. Because while the lights vary in appearance from vehicle to vehicle, all have the same basic meaning: There's a problem with the car's emissions system. The on-board diagnostics system C203A and engine control unit are in charge of monitoring a bunch of different transmission fluid temperature sensor circuit intermittent, and if they get a reading that's a little out of whack, up pops the check engine light.
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C203A is a kind of Chassis Trouble Code
Diagnosing chassis noises can be one of the most frustrating problems technicians face. Fortunately, manufacturers have engineered noise, vibration and harshness (NVH) diagnostic techniques and equipment to find the source of the noise. |
You can view according C203A DTC for your car model. We selected several models to see obd2 solutions click and view it.
| +C203A Caterham Roadsport | +C203A Bmw 8 | +C203A Riley Elf | +C203A Mcc Silverpulse | +C203A Alvis Fwd |
Engine OBD 2 Codes website is a freeware resource center for engine trouble codes.
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