What it means
Exhaust Aftertreatment Fuel Injector A Control Circuit High: the control-circuit voltage is above the expected range. This injector doses fuel into the exhaust to raise temperature for diesel particulate-filter regeneration; it does not fuel the engine.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Aftertreatment fuel injector A sprays fuel into the exhaust to help raise exhaust temperature during diesel particulate filter (DPF) regeneration; it does not supply fuel to the engine. The control module monitors injector A’s control circuit and sets P20CE when its voltage is higher than expected, which can happen if the wire is shorted to battery power or the connection has excessive resistance.
Common causes
Most likely first.
- Short to B+
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check engine light on
- Possible exhaust smoke or fuel odor during regeneration
- DPF regeneration may be impaired
How to diagnose it
- Record freeze-frame data and check regeneration status and injector A command data to see when the high-circuit fault occurred.
- With the exhaust cool, inspect injector A’s connector and harness for corrosion, damaged insulation, or a wire pinched against a power source.
- Check the connector terminals for corrosion, looseness, or poor contact that could raise circuit resistance.
- Using the wiring diagram, test injector A’s control wire for a short to battery voltage and check continuity between the injector and control module.
- If wiring and connections pass, test injector A and its control circuit against the manufacturer’s specification before replacing a component.
Common fixes
- Repair damaged wiring that is contacting a power source.
- Clean or repair corroded or loose injector A connector terminals.
- Repair a short to battery power in injector A’s control circuit.
- Replace injector A if it fails testing to the manufacturer’s specification.
Can I keep driving?
If the vehicle runs normally and there is no smoke or fuel odor, a short trip to a repair location may be possible, but avoid repeated or prolonged driving because DPF regeneration may be impaired. Stop if heavy smoke or a strong fuel odor develops.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.