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.
Some systems require that the actuator has an adequate supply of brake fluid. Low brake fluid levels can mimic the symptoms of code C3748, so consult the manual to locate the brake fluid reservoir. Bear in mind that a low fluid level can set code C3748 on some applications, so make sure that on fluid operated systems the fluid level is up to the mark before starting an electrical diagnosis.
The scent may C3748 signal oil or coolant leaking from their normally closed-loop systems, or it may indicate dangerous exhaust gases invading your car's interior. Car and truck exhaust contains toxic gases such C3748, so if the inside of your car abs inlet valve coil rr circuit short to battery as if you were standing behind your car, get out and get it fixed. Fight the urge to take a little nap first. So sleepy. That's the carbon monoxide talking, friends. At least open a window on your way to the shop.
Difficulty Level (Soso)
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Repair Time (50 Min.)
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Cost Prediction : $ 90-120 |
C3748 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 C3748 DTC for your car model. We selected several models to see obd2 solutions click and view it.