Exhaust Aftertreatment Fuel Injector Control Circuit Low
The P20CD 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 itself. This can prevent proper regeneration, leading to increased emissions and potential damage to the aftertreatment system.
1. Most Common Causes
- Open or shorted wiring in the injector control circuit
- Faulty exhaust aftertreatment fuel injector
- Corroded or loose electrical connector
- Failed PCM (rare)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced fuel economy
- Increased exhaust emissions
- Possible DPF regeneration issues (e.g., frequent regens or inability to regen)
3. Step-by-Step Diagnosis
Step 1: Scan for additional codes and freeze frame data to confirm P20CD.
Step 2: Visually inspect the injector wiring and connector for damage, corrosion, or loose pins.
Step 3: Use a multimeter to check for continuity and voltage at the injector harness; compare to manufacturer specs.
Step 4: Test the injector resistance; if out of range, replace the injector.
Step 5: If wiring and injector are good, check PCM output signals; consider PCM replacement if necessary.
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 aftertreatment system. Short trips may be okay, but the vehicle should be diagnosed promptly.
How much does it cost to fix?▼
The cost typically ranges from $150 to $400, including parts and labor. The injector itself costs $50-$150, and labor adds $100-$250 depending on the vehicle and shop rates.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.