Exhaust Aftertreatment Fuel Injector Circuit Low
The P2699 code indicates that the powertrain control module (PCM) has detected a low voltage or resistance condition in the electrical 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 condition can be caused by a faulty injector, damaged wiring, poor electrical connections, or a malfunctioning PCM. This issue can prevent proper DPF regeneration, leading to increased emissions and potential engine performance problems.
01. Most Common Causes
- Faulty exhaust aftertreatment fuel injector
- Damaged or corroded wiring/connectors in the injector circuit
- Open or short to ground in the injector circuit
- Failed PCM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced fuel efficiency
- DPF regeneration issues (frequent or incomplete regeneration)
- Possible black smoke from exhaust
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for related codes (e.g., P2697, P2698).
Step 2: Visually inspect the injector and its wiring harness for damage, corrosion, or loose connections.
Step 3: Test the injector resistance with a multimeter; compare to manufacturer specifications (typically 0.5-2 ohms).
Step 4: Check for voltage at the injector connector with the ignition on; should be battery voltage (12V).
Step 5: If wiring and injector are okay, test the PCM output circuit for continuity and shorts.
04. Commonly Affected Makes
05. 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 aftertreatment system. Short trips may be okay, but the issue should be diagnosed promptly.
How much does it cost to fix?▼
The cost to fix P2699 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.