Exhaust Aftertreatment Fuel Injector Control Circuit Low
The P20D3 code indicates that the powertrain control module (PCM) has detected a low voltage condition in the control circuit of the exhaust aftertreatment fuel injector. This injector is used in diesel engines to introduce fuel into the exhaust stream for regeneration of the diesel particulate filter (DPF) or to raise exhaust temperature for selective catalytic reduction (SCR) systems. A low circuit voltage typically points to a wiring issue, a faulty injector, or a problem with the PCM.
1. Most Common Causes
- Open or shorted wiring in the injector control circuit
- Faulty exhaust aftertreatment fuel injector
- Corroded or damaged connector at the injector
- Failed PCM (rare)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced fuel efficiency
- Increased exhaust emissions
- Possible DPF regeneration issues or frequent regeneration cycles
3. Step-by-Step Diagnosis
Step 1: Scan for additional codes and note freeze frame data.
Step 2: Visually inspect the injector wiring and connector for damage, corrosion, or loose connections.
Step 3: Using a multimeter, check the injector control circuit for continuity and proper voltage (typically 12V or 5V reference).
Step 4: Test the injector resistance; compare to manufacturer specifications.
Step 5: If wiring and injector are okay, check PCM output signals; consider PCM replacement if all else fails.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances with this code as it can lead to incomplete DPF regeneration, increased emissions, and potential damage to the exhaust system. You may notice reduced performance and fuel economy.
How much does it cost to fix?▼
The cost to fix P20D3 typically ranges from $150 to $400, including parts and labor. The injector itself can cost $50-$150, and labor for diagnosis and replacement is usually $100-$250.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.