PO420 – Powertrain trouble code (manufacturer-specific)
| Code | Fault Location | Probable Cause |
|---|---|---|
| PO420 | Manufacturer-specific powertrain code. The second character 'O' marks this as defined by the vehicle manufacturer rather than the SAE standard, so its exact meaning varies between makes. We do not yet have a verified definition for this code. | Meaning varies by manufacturer - check your make's service information. Read the freeze-frame data with a scan tool and note any codes stored alongside it before replacing parts. |
Look this code up for your make
Manufacturer-specific codes mean different things on different vehicles. Browse by make:
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Reading PO420 on your car
PO420 is a manufacturer-specific code. Most inexpensive Bluetooth adapters read generic engine codes only and cannot reach these systems at all – reading it, and getting the manufacturer’s own description of the fault, needs a scanner that talks to the other modules.
Know what PO420 means on your vehicle? Tell us in the comments and we will get it verified and written up.
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Help Us Help You
We have not gotten around to publishing a technical guide specifically for PO420 – Powertrain trouble code (manufacturer-specific) yet.
Tell us about your vehicle in the comments below - make, model, year, mileage and engine, plus what the car is actually doing - and we will use it to decide which guides to write next. The codes people ask about most are the ones we cover first.