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.
Circuit High Input codes like C3988 are mostly caused by defective alternators that develop excessive voltages, although there may be other causes as well, such as short circuits that 'leak' current into a particular system from other, unrelated systems that work on higher voltages. Note that in the case of short circuits that leak power into a control circuit, there is likely to be other, seemingly unrelated trouble codes present along with the code(s) being investigated. Diagnosing a 'high input' code will always involve a thorough testing of the charging system as a first step, followed by measures to isolate the system from all other possible sources of power during resistance, continuity, and reference voltage tests.
Difficulty Level (Easy)
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Repair Time (45 Min.)
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| Cost Prediction : $ 80-120 |
If your prndl input #3 circuit failure 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 C3988 and engine control unit are in charge of monitoring a bunch of different prndl input #3 circuit failure, and if they get a reading that's a little out of whack, up pops the check engine light.
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C3988 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 C3988 DTC for your car model. We selected several models to see obd2 solutions click and view it.
| +C3988 Aston Martin Db9 | +C3988 Fiat Stilo | +C3988 Pontiac Chieftan | +C3988 Honda Acura El | +C3988 Dacia Logan |
Engine OBD 2 Codes website is a freeware resource center for engine trouble codes.
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