P2699: Exhaust Aftertreatment Fuel Injector A Circuit Low

What it means

Voltage on the 7th injector control line is below the expected window. Usually a short to ground or a shorted solenoid coil.

At a glance

• Usually lights the check-engine light

How it works

Injector A is the exhaust aftertreatment fuel doser used to raise exhaust temperature for active DPF regeneration. P2699 sets when the controller sees voltage on its control circuit below the expected range, commonly from a short to ground, a shorted injector coil, or a poor connection.

Common causes

Most likely first.

1. Control wire shorted to ground
2. Internal short in injector coil
3. Connector pins corroded - high contact resistance

Symptoms

• Check-engine light
• DPF warning light
• More frequent or unsuccessful DPF regeneration

How to diagnose it

1. Review freeze-frame data and DPF regeneration status to confirm when the low-circuit fault appears.
2. With the system off as specified by the manufacturer, inspect injector A's connector and harness for chafing, corrosion, contamination, or pin damage.
3. Check connector fit and terminal condition, since a corroded or loose connection can disrupt the circuit.
4. Test the control wire for a short to ground and check the injector coil for an internal short using the manufacturer's procedure.
5. If the wiring and injector pass, check circuit voltage and the controller driver against the wiring diagram and manufacturer specifications.

Common fixes

• Clean or repair corroded, loose, or damaged injector A connector terminals.
• Repair a control wire that is shorted to ground or rubbed through.
• Replace injector A if its coil is shorted and fails the specified test.
• Repair the controller driver only after the circuit and injector have been verified.

Can I keep driving?

Cautious driving is generally possible if there is no severe power loss, but avoid repeated short trips and follow any DPF warning. The dosing fault can interrupt regeneration and allow soot to accumulate in the filter.