P2697: Exhaust Aftertreatment Fuel Injector A Circuit/Open
What to do
You will probably feel nothing at first, and the particulate filter warning may appear later.
What this part does is worth knowing: it sprays a small amount of diesel into the exhaust to raise the temperature so the particulate filter can burn off its soot. That is normal and intended. The alternative method — injecting extra fuel inside the engine — washes fuel down the bores into the oil, so a vehicle with this injector is one whose oil is being protected from dilution.
Why to fix it reasonably promptly: without dosing, the filter will not regenerate properly and will gradually block, which is a much larger bill. And on vehicles that fall back to in-cylinder injection instead, you get the oil dilution the injector was fitted to avoid — so keep an eye on the oil level, and treat a level that is rising rather than falling as a reason to stop and get it looked at.
The fault is usually the connector rather than the injector — it sits on the exhaust, in the heat and the road spray, which is hard on a plug.
What this code means
An open circuit in the control of the injector that sprays fuel into the exhaust system.
Fuel injected into the exhaust sounds like a fault and is entirely deliberate, and understanding why explains what this part is protecting.
A diesel particulate filter must periodically burn off the soot it has trapped, and that needs exhaust temperatures far above what a diesel produces in ordinary driving. There are two ways to supply the extra heat, and they are not equivalent.
The common way is a post-injection inside the cylinder — extra fuel injected late, after the main combustion, which burns in the exhaust rather than pushing the piston. It works, and it has a well-known cost: some of that late fuel lands on the cylinder wall and is scraped down into the sump, so oil level rises, oil is diluted with diesel, and its ability to protect bearings falls away. Vehicles doing many short journeys and many interrupted regenerations can dilute their oil badly enough to damage the engine.
An exhaust-mounted fuel injector avoids that entirely by putting the fuel where it is needed instead of routing it through the engine. It sits upstream of the oxidation catalyst, sprays a metered amount of diesel, and the catalyst burns it to raise the temperature going into the filter. A vehicle fitted with one is a vehicle whose oil is being protected, which is worth knowing because it changes what the part is worth.
It is not the same thing as a reductant injector. That one sprays urea solution for oxides of nitrogen and is part of a different system entirely — the names are close enough to be confused, and the parts are not interchangeable.
With the circuit open, the module cannot dose. Regeneration will not complete, so the filter loads progressively — nothing dramatic today, and a blocked filter in a few months. Some vehicles fall back to in-cylinder post-injection, which keeps the filter working while reintroducing exactly the oil dilution the injector existed to prevent.
The connector is the first suspect and for a specific reason: it lives on the exhaust. Heat cycling, road spray from underneath and corrosion at the joint account for most of these.
Likely causes
Start here
- Corroded or loose connector · easy
- Open circuit in injector wiring · moderate
- Heat damage to sensor or wiring · moderate
- Faulty exhaust aftertreatment fuel injector · moderate
Less common
- Damaged wiring harness · moderate
Symptoms
Components involved
Information, not instruction
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