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.
A good starting point in your diagnosis is checking all system fuses and fusible links. This can be done using the DVOM on the voltage setting. You will want to test the fuses with circuits loaded. Some fuses will appear normal until a load is placed on their respective circuit; at which point they will fail. This has been the cause of many 'phantom malfunctions'. Consult your vehicle information source for fuse and fusible link locations. If all fuses are in working order, you may want to check TCM relay operation by swapping identical relays. Usually the horn relay, starter relay, fuel pump relay, air conditioning clutch relay, and controller relays are similar enough in design to swap for diagnostic purposes.
Difficulty Level (Expert)
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Repair Time (60 Min.)
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| Cost Prediction : $ 75-90 |
When you turn on the ignition, the Service Engine Soon or Check Engine C3494 light should flash briefly, indicating that the OBD system is ready to scan your vehicle for any malfunctions. After this brief flash, the light should stay off while you drive as long as no problems are detected. If passenger door lock switch circuit shorted to ground so, you'll be glad to know that your vehicle is equipped with an early warning system that could save you time, money, and fuel in addition to helping protect the passenger door lock switch circuit shorted to ground.
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C3494 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 C3494 DTC for your car model. We selected several models to see obd2 solutions click and view it.
| +C3494 La Buire 10 Hp | +C3494 Nissan Platina | +C3494 Citroen Jumpy | +C3494 Bmw 325 | +C3494 Holden Jd |
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