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Exhaust and Emissions

Everything downstream of the exhaust valve, plus the systems that clean up combustion: oxygen sensors, catalytic converters, EGR and evaporative emissions. Many faults reported here are honest measurements of a problem that originates upstream in fuelling or ignition.

1340 codes · 41 components · 4 live parameters

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Components

Live parameters to watch

PID Parameter Unit Conversion
01:2C Commanded EGR How much exhaust gas recirculation the module is asking for. Compare with EGR error to see whether the valve is complying — a commanded value with a large error means the valve is stuck, usually with soot. % A × 100 / 255
01:2D EGR error Difference between commanded and actual EGR position. Large sustained error is the signature of a carboned-up valve, which is among the most common diesel faults there is. % (A / 1.28) − 100
01:2E Commanded evaporative purge How much stored fuel vapour the module is drawing from the charcoal canister. A purge valve stuck open dumps vapour continuously and produces a rich condition that looks like a fuelling fault. % A × 100 / 255
01:3C Catalyst temperature — Bank 1 Sensor 1 Catalytic converter temperature. Runs hot when the converter is working, and runs alarmingly hot when unburnt fuel from a misfire is being burnt inside it — which is precisely the damage a flashing warning lamp is warning about. °C (((256 × A) + B) / 10) − 40

Trouble codes

High 160
Moderate 433
Low 80

Information, not instruction

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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.

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