P0421 on the 2018 Chevrolet Equinox
The bulletins listed name this code in NHTSA's summary, or are about the same components. A bulletin or a recall listed here may apply to the model year. None of it is a diagnosis.
Nobody has written a description of this code yet.
| PIP5615 | 2019-03-18. Service bulletin. This Preliminary information communicates that a Engine Control Module (ECM) service update calibration for P0421. |
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| PIP5615A | 2019-03-11. Service bulletin. This Preliminary information communicates that a Engine Control Module (ECM) service update calibration for P034A, P0421, P050F, P059F, P111E, P11DC, P122D, P1488, P220B, P22FE, P2457, P2463, P2BAA. |
| 18209 | 2018-08-20. Service bulletin. 18209 - Service Update. Certain vehicles equipped with a 1.6L diesel engine (RPO LH7), may have been built with an improper alignment of the clamp/gasket assembly connecting the turbocharger to the catalytic converter. This condition may cause a diesel exhaust leak and/or smoke from the underhood area of the vehicle. In addition, a check engine indicator may set with diagnostic trouble code P0421. Dealers are to inspect and replace the turbocharger to catalytic converter clamp/gasket as necessary. |
| 18NA120 | 2018-05-21. Service bulletin. This technical bulletin provides a procedure to reposition the exhaust clamp to correct a condition of Exhaust Smell in Cabin and/or DTC P0421 Set due to a miss installed clamp. |
4 on file from NHTSA, as of 2026-10-19. See them in the bulletin list. A bulletin lists model years: read the document for which vehicles it concerns.