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.
In most cases, the TCM is integrated into a single housing with the PCM. Nevertheless, the section of the module which controls (automatic) transmission function may be powered up separately. In any case, the TCM is typically powered using switched (only present with the ignition switch in the ON, start, or run position) voltage. This circuit is normally equipped with a fuse, fusible link, and/or a relay. Frequently, the PCM and TCM are powered using the same relay albeit by separate circuits. Access to a reliable vehicle information source will yield necessary details of the TCM power circuit for the specific vehicle in question.
Difficulty Level (Soso)
|
Repair Time (30 Min.)
|
| Cost Prediction : $ 80-120 |
If your engine speed input circuit range/performance 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 B3021 and engine control unit are in charge of monitoring a bunch of different engine speed input circuit range/performance, and if they get a reading that's a little out of whack, up pops the check engine light.
|
B3021 is a kind of Body Trouble Code
Auto body problems aren't always easy to spot. Diagnosing auto body problems sometimes requires a little know-how. In this section you'll find articles dedicated to teaching you how to diagnose auto body problems. |
You can view according B3021 DTC for your car model. We selected several models to see obd2 solutions click and view it.
| +B3021 Mazda Mazda 3 Iii | +B3021 Lada Niva | +B3021 Peugeot 203 | +B3021 Nissan Aa-x | +B3021 Lexus Minority Report |
Engine OBD 2 Codes website is a freeware resource center for engine trouble codes.
Copyright 2017 © All rights reserved