Exhaust Aftertreatment Fuel Supply Control Circuit High
The P20DA code indicates that the powertrain control module (PCM) has detected a high voltage condition in the exhaust aftertreatment fuel supply control circuit. This circuit controls the fuel injector that supplies fuel to the diesel particulate filter (DPF) for regeneration. A high voltage reading typically points to a short to power, a faulty fuel injector, or a damaged wiring harness.
01. Most Common Causes
- Short to power in the fuel injector control circuit
- Faulty exhaust aftertreatment fuel injector
- Damaged wiring or connectors in the circuit
- Failed PCM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced fuel efficiency
- DPF regeneration issues or frequent regeneration cycles
- Possible engine power loss
03. Step-by-Step Diagnosis
Step 1: Scan for additional codes and freeze frame data.
Step 2: Visually inspect the wiring and connectors for damage, corrosion, or shorts.
Step 3: Test the fuel injector resistance and compare to manufacturer specs.
Step 4: Check for voltage at the injector connector with key on; should be battery voltage or as specified.
Step 5: If wiring and injector are okay, test the PCM output circuit for proper operation.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it can lead to incomplete DPF regeneration, causing clogging and potential engine damage. Short trips to a repair shop are acceptable.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, depending on whether the injector needs replacement or just wiring repair. Diagnostic fees are extra.