P20CE: Exhaust Aftertreatment Fuel Injector A Control Circuit High

The control line of the hydrocarbon doser is shorted to battery voltage. GM's diesel tables 18OBDG04 and 25OBDG04A detect it while the driver is switched on: current above roughly 8 to 11 A for a set time, or above about 16 to 22 A at once, counts as a short to power. GM rates it Type B, so the MIL follows after two trips; the LML/LGH Duramax (15OBDG09) uses a voltage check in the on state. The doser can then no longer be opened on command. Hino's J08E manual names P20CE among the codes to clear before diagnosing a regeneration complaint. Open circuit and short to ground are P20CB and P20CD.

Medium severity. Can I keep driving?Drive as little as possible and go to a repair shop. If you smell fuel or the engine is shaking badly, do not keep driving.

Symptoms

Check engine light on
Active regeneration not possible
Rising soot load, later reduced power

Most likely causes

Control wire touching a powered wire in a damaged harness
Doser solenoid with shorted turns drawing too much current
Faulty output stage in the engine control module

What to check, in order

Start with the simplest. You can tick off each step.

Check the connector and wiring of the injector indicated
Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
Measure the resistance and compare it with the manufacturer's specification
Check the control signal with an oscilloscope; on direct injection or diesel engines, leave this to a repair shop because of the high voltages
On diesels, check the per-cylinder injection corrections

Good to know

Repair difficulty: medium
It can trigger limp mode.
It affects emissions.

What each character of P20CE means

P: Powertrain: engine and transmission
2: Generic code: same on every make
0: Subsystem depends on the code range
CE: Specific fault in that system

Frequently asked questions

Can I keep driving with code P20CE?

Drive as little as possible and go to a repair shop. If you smell fuel or the engine is shaking badly, do not keep driving.

What causes code P20CE?

The most common causes are: control wire touching a powered wire in a damaged harness; doser solenoid with shorted turns drawing too much current; faulty output stage in the engine control module.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.