P2698 indicates that the powertrain control module (PCM) has detected a performance issue with the exhaust aftertreatment fuel injector, which is responsible for injecting fuel into the exhaust stream to assist in diesel particulate filter (DPF) regeneration or selective catalytic reduction (SCR) processes. This code typically means the injector is not delivering the expected fuel quantity or flow rate.
The injector itself may be clogged, leaking, or mechanically failed, preventing proper fuel delivery into the exhaust stream.
Low fuel pressure, restricted fuel lines, or a failing fuel pump can prevent the injector from receiving adequate fuel for proper operation.
Damaged, corroded, or loose wiring or connectors between the PCM and the injector can disrupt signal or power delivery.
A rare but possible cause is an internal failure in the PCM’s injector control circuit, though this is uncommon compared to mechanical or electrical issues.
Fuel with excessive impurities or incorrect additives can clog or damage the injector over time.
No, the PCM is rarely the cause of this code. The issue is almost always related to the injector itself, fuel supply, or wiring. Replacing the PCM should only be considered after all other potential causes have been thoroughly tested and ruled out.
Driving with this code active may lead to reduced engine performance, failed DPF regeneration, or increased emissions. Prolonged driving could result in further damage to the aftertreatment system or engine.
A clogged or failed injector may exhibit symptoms like poor fuel delivery during regeneration cycles, unusual exhaust smoke, or failed flow tests. Professional diagnostic tools can measure injector performance directly.
Cleaning may resolve the issue if the injector is clogged by fuel deposits or contaminants. However, if the injector is mechanically damaged or worn, cleaning will not restore proper function, and replacement may be necessary.