Frigidaire Factory Service ManualFault Code: i40

Frigidaire Dishwasher Error Code i40: Water Level Pressure Transducer Circuit Fault

The main control board detects an analog voltage signal from the pressure transducer that is out of calibration range or completely shorted.

Target Appliance

dishwasher

OEM Certified Technical Diagnostic Tree

Diagnostic Tool Required

Digital Multimeter

Measure Ohms resistance, continuity & line voltage.

Triage Complexity

Advanced Diagnostic

4 Sequential manufacturer inspection branches.

Sequential Factory Diagnostic Tree

Perform each diagnostic step in order. Disconnect electrical power and turn off utility shutoffs before inspecting wiring or internal mechanical assemblies.

Step 1: Physical & Electrical InspectionMultimeter & Visual

Action: Disconnect electrical power, remove kickplate, and access the pressure transducer mounted in lower right sump.

Bench Test: Check transducer wiring plug for loose wire terminal pins or water dripping onto connector.

Expected Standard: Dry, clean connector securely locked into sensor receptacle.

If Failed / Out of Spec:

Dry connection and repair wire harness terminal.

If Passed:

Proceed to Step 2.

Step 2: Physical & Electrical InspectionMultimeter & Visual

Action: Remove pressure sensor from sump by rotating quarter-turn and inspect sensor orifice.

Bench Test: Check internal silicone membrane for gelatinous grease, food seeds, or calcium encrustation.

Expected Standard: Orifice clean and unobstructed.

If Failed / Out of Spec:

Clean sensor port with warm water or replace pressure sensor (5304504077).

If Passed:

Proceed to Step 3.

Step 3: Physical & Electrical InspectionMultimeter & Visual

Action: Measure DC reference voltage supplied from control board to the pressure sensor harness.

Bench Test: Reconnect power, start test cycle, and measure DC voltage across VCC and GND pins.

Expected Standard: Steady 5.0V DC reference voltage.

If Failed / Out of Spec:

Replace main electronic control module (5304512731).

If Passed:

Proceed to Step 4.

Step 4: Physical & Electrical InspectionMultimeter & Visual

Action: Measure signal output voltage pin relative to ground with empty tub vs filled tub.

Bench Test: Measure analog voltage output.

Expected Standard: Approximately 0.5V DC when empty, rising linearly to 2.5V–3.5V DC as water fills tub.

If Failed / Out of Spec:

Replace defective pressure transducer sensor (5304504077).

If Passed:

Replace main control module (5304512731).

Verified OEM Replacement Parts

Cross-referenced factory part numbers for Frigidaire dishwasher error code i40. Always replace defective components with authentic OEM parts to maintain UL safety certification.

Component Name	OEM Part Number	Manufacturer	Status
Sump Water Level Pressure Transducer	`5304504077`	Frigidaire	Direct Fit OEM
Main Electronic Control Board Assembly	`5304512731`	Frigidaire	Direct Fit OEM
Sump Sensor O-Ring Seal Kit	`5304504078`	Frigidaire	Direct Fit OEM

Need Local Diagnostic Assistance?

Connect with a Certified Frigidaire Technician in Your Area

If multimeter testing reveals an internal short, locked motor, or fried control board, let an experienced local technician complete the repair with certified OEM replacement parts.

Call for Immediate Technician Dispatch Search Another Code

Frequently Asked Questions: Frigidaire i40

What causes Frigidaire dishwasher error code i40?

The main control board detects an analog voltage signal from the pressure transducer that is out of calibration range or completely shorted.

Can I reset the i40 code by unplugging the dishwasher?

While disconnecting power for 5 minutes may temporarily clear the display control memory, the i40 code will reoccur once the microcontroller detects the mechanical or electrical fault again.

What OEM replacement parts are required for Frigidaire i40?

Common OEM replacement components include: Sump Water Level Pressure Transducer (OEM #5304504077), Main Electronic Control Board Assembly (OEM #5304512731), Sump Sensor O-Ring Seal Kit (OEM #5304504078).