Engine-Codes - Chevrolet - P0421 Chevrolet

P0421 Chevrolet Code - Catalyst 1 Low Efficiency

- Code Popularity: 275 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
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What are the Possible Causes of the DTC P0421 Chevrolet?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • Faulty Oxidation Catalytic Converter
  • Faulty Diesel Particulate Filter (DPF)
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How to Fix the DTC P0421 Chevrolet?

Check the 'Possible Causes' listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

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What is the Cost to Diagnose the Code?

Labor: 1.0

The cost to diagnose the P0421 Chevrolet code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair shops charge between $75 and $150 per hour.

What are Code Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)

What Does the P0421 Chevrolet Code Mean?

The main function of the Close Coupled Diesel Oxidation Catalyst (CCDOC) is to control emissions of non-methane hydrocarbons and Carbon Monoxide (CO). Its secondary function is to assist with the Diesel Particulate Filter (DPF) regeneration, by obtaining and sustaining the temperature necessary for regeneration. In order to generate the high exhaust temperatures needed for regeneration, the aftertreatment system increases exhaust temperatures by injecting diesel fuel into the exhaust system via post-injection. The injected fuel is converted into heat by the DOC to incinerate soot accumulated in the DPF. The Engine Control Module (ECM) monitors the exhaust gas temperature sensor 1 and 2 to determine if catalyst downstream temperatures are achieved during a DPF regeneration.

P0421 Chevrolet Code - Catalyst 1 Low Efficiency

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