P1926 — Intermittent Fuel Additive Level Circuit Fault

P1926 — Intermittent Fuel Additive Level Circuit Fault. P1926 is an intermittent fuel-additive level-circuit fault and is not, by itself, proof of major engine failure.

For Ford vehicles

fuel additive level circuit – intermittent fault

vehicle

Is it safe to drive?

Drive cautiously and schedule diagnosis P1926 is an intermittent fuel-additive level-circuit fault and is not, by itself, proof of major engine failure. Driving may be possible if there are no other warnings, but continued operation can prevent proper additive dosing or regeneration. Avoid extended driving if the additive warning remains, the reservoir is empty, or the vehicle cannot complete regeneration.

Typical symptoms

P1926 stored as a current, pending, or history code
Check-engine warning light may illuminate with P1926
Fuel-additive level may appear unavailable, incorrect, or intermittently low
Additive warning message may appear on the instrument panel
Additive dosing or exhaust regeneration may fail or be delayed
The fault may return after refilling, clearing the code, or driving over rough roads

Common causes

Low or depleted fuel additive causing the level sensor to report an invalid condition
Loose, corroded, or water-contaminated connector at the additive level sensor
Chafed or damaged wiring causing an intermittent open or short in the P1926 sensing circuit
Marginal internal failure of the additive reservoir level sensor
Faulty sensor ground, supply, or reference connection
Obstructed additive reservoir pickup or incorrect additive level calibration

How to diagnose with an OBD scanner

Read P1926 and related data Connect an OBD2 scanner, including an ELM327 adapter with AIScanAuto or equivalent software, and review stored, pending, and permanent codes. Save the freeze-frame information and check for fuel-additive sensor or communication codes.
Check the additive reservoir Inspect the fuel-additive reservoir for the correct fluid, sufficient level, contamination, damage, and an obstructed pickup. If the fluid level is low, refill only with the type specified by the vehicle manufacturer before continuing the diagnosis.
Inspect the level-sensor circuit Examine the level-sensor connector, wiring harness, relevant grounds, and wiring leading toward the control module. Look for corrosion, heat damage, pin pushing, chafing, and conductors that flex or rub against nearby components.
Perform an intermittent wiggle test While monitoring P1926 live sensor data with an OBD2 scanner, gently move the harness and connector and lightly rock the vehicle if safe. A dropped signal, erratic reading, or newly displayed P1926 indicates an intermittent connection or wiring concern.
Test the sensor electrically Back-probe the sensor and control-module connector with a multimeter or oscilloscope. Compare the supply, ground, and signal behavior with the manufacturer specifications to identify an open circuit, short circuit, or out-of-range sensor.
Repair and verification drive Repair confirmed wiring or connector faults, or replace the level sensor if its signal fails specifications. Clear P1926, refill the reservoir if required, and verify the level reading through a complete fill-and-regeneration cycle using the service information for that vehicle.

Approximate repair cost

Independent-shop estimate: approximately $125–$450 for diagnosis and a likely connector, wiring, or level-sensor repair. These figures are estimates only and vary by region, vehicle access, labor time, and parts availability; control-module work may cost more.

Common questions

Does P1926 always mean the additive level sensor has failed?

No. P1926 may result from low additive, a loose connector, damaged wiring, a poor ground, or an intermittent level-sensor failure, so those items should be checked before buying a sensor.

Can the vehicle be driven with P1926 stored?

It may be driven cautiously if no other serious warning is present, but the fault should be diagnosed promptly because additive dosing or regeneration may be impaired when the circuit becomes active.

How is an intermittent P1926 fault confirmed?

Technicians monitor the live additive-level data while checking the reservoir, flexing the wiring, and testing the connector and sensor. The fault must be reproduced or the signal shown to fail specifications before replacement is justified.

Will clearing the P1926 code repair the problem?

Clearing P1926 only removes the stored information; it does not correct a loose connector, damaged circuit, incorrect fluid level, or defective sensor. The fault can return if the underlying cause remains.

P1926 — ---

P1926 appears when your vehicle's engine or transmission control module detects a fault within a sensor and actuator circuit. This code doesn't trigger from a single bad reading — the module requires the fault condition to repeat under specific operating parameters before activating the check engine light. The exact component and circuit vary by manufacturer, but the underlying issue is always electrical: either a failed component or a problem with the wiring and connections that carry its signals.

When P1926 sets, the control module captures a freeze frame — a snapshot of engine load, RPM, coolant temperature, and vehicle speed at the precise moment the fault occurred. This data narrows your diagnosis considerably. If the code was triggered during hard acceleration, you focus testing there. If it appeared at idle, that's where you concentrate your efforts. An intermittent fault that never reproduces under normal conditions might require simulating the recorded freeze frame data to confirm the repair.

Symptoms of P1926

The check engine light illuminates and remains on
The affected system operates intermittently or fails to function entirely
Fuel consumption increases in some vehicle applications
Reduced engine performance or limp-home mode activation
Additional warning lights may accompany the check engine indicator
In rare cases, the vehicle may hesitate or exhibit unstable idling

Common Causes

Failed sensor or actuator within the affected circuit
Corroded, loose, or physically damaged electrical connector
Compromised ground connection at the component or control module
Open circuit — broken wire interrupting signal or power delivery
Shorted circuit — wire contacting ground or another voltage source
Blown fuse protecting the affected circuit
Chafed wiring insulation allowing shorts to chassis ground

How to Diagnose P1926

Connect an OBD2 scanner and confirm P1926 is stored. Save all freeze frame data before clearing — you need those conditions to reproduce the fault during testing.
Pull any additional diagnostic trouble codes stored alongside P1926. Related codes often point directly to the root cause, whether it's a power supply issue, ground fault, or signal problem.
Consult manufacturer technical service bulletins for your specific make, model, and model year. Many recurring P1926 faults have documented factory solutions, including software updates that prevent false triggers.
Perform a thorough visual inspection of the wiring harness and connectors associated with the affected circuit. Look for cracked insulation, green corrosion buildup, pushed pins, or melted plastic from heat damage.
Test electrical values at the component connector: reference voltage from the control module, ground integrity, and signal continuity through the circuit. Compare readings to manufacturer specifications.
Clear P1926, complete a drive cycle matching the freeze frame conditions, and verify the code does not return. If it recurs immediately, the fault is present and active.

Repair Options and Costs

Wiring harness repair or connector replacement: $80–$250
Sensor or actuator replacement: $150–$500
Control module diagnosis and repair: $300–$1,000

Prices reflect typical independent shop labor rates in the United States and cover both parts and professional installation.

Total Repair Cost for P1926

The final bill depends entirely on which component failed. Wiring issues sit at the low end of the spectrum and are the most frequently encountered root cause. Sensor and actuator failures fall in the middle range. Control module problems, while less common, push costs toward $1,000 depending on whether the module can be repaired or requires replacement. An accurate diagnosis before purchasing parts prevents unnecessary expense — the most costly repair is rarely the first one to investigate.

Can You Drive with P1926?

Short term, most vehicles remain drivable with P1926 stored. You may notice reduced performance or limited functionality from the affected system. However, if the fault causes stalling, prevents starting, or triggers warnings related to braking or steering assist, the situation demands immediate attention. Treat P1926 as a maintenance item to schedule promptly rather than an emergency requiring roadside assistance.