This code indicates a shorted thermistor / OWI (Optical Water Indicator) sensor circuit. The OWI module monitors water temperature and clarity (turbidity) in the sump so the control can choose wash temperatures, heater on-time, and rinse strategy. When the control detects an electrical short in the thermistor leg of the OWI, it flags 3–2 (or F3E2) and may pause or cancel the cycle to protect the electronics.
How the Thermistor/OWI Affects Wash Performance
During a cycle, the dishwasher samples water temperature and soil load. If the thermistor reading collapses because of a short, the control loses a reliable temperature signal. That can lead to lukewarm washes, heaters that never energize, or a program that aborts early. The error code prevents further heating until you restore a valid thermistor signal.
Common Triggers and Where Problems Hide
Most failures trace to moisture intrusion at the OWI connector, pin damage or oxidation on the low-voltage pins, or harness sections rubbed through where the wiring passes the tub or frame. Less commonly, the sensor’s internal thermistor fails short. In rare cases, a surge damages the control’s thermistor input, but you should exhaust sensor and harness checks before suspecting the board.
Safety and Initial Setup
Cut power at the breaker or unplug the machine before opening toe-kick panels. Place a towel under the sump area and photograph connectors before you unplug them, so reassembly matches the original routing. Record the model and serial number from the door frame; you’ll need them for parts verification.
Visual Inspection That Actually Helps
Access the sump and locate the OWI on the side of the tub or sump housing. Confirm the body sits flat and locked, with the O-ring or seal intact. Inspect the two-part connector at the OWI and the mating harness for moisture, detergent residue, or green/white corrosion; those films can bridge pins and mimic a short. Trace the harness toward the control, looking for flattened sections, insulation nicks, or areas where the harness rubbed against metal. Reseat both ends firmly until the locks click.
Electrical Checks Without Guesswork
With power off, disconnect the OWI and measure across the thermistor pins with a multimeter. At room temperature the thermistor should show a finite resistance (not near zero ohms). A near-zero reading indicates an internal short and requires replacement. If the sensor measures plausibly, check continuity from the OWI connector back to the control connector on each thermistor lead to rule out a harness short to ground or between conductors. Flex the harness gently while measuring to expose intermittent faults. If both the sensor value and harness continuity look normal, the control input may be damaged and will need evaluation after you test with a known-good sensor.
Cleaning, Reseating, and When to Replace
Dry any moisture at the OWI connector, clean oxidized pins with contact cleaner, and reseat the connector. If the sensor shows a shorted reading or the connector shell is heat-stressed or cracked, replace the thermistor/OWI sensor with the correct part for your model and install a fresh seal. If you find chafed wiring, replace the affected harness section rather than taping it; low-voltage signal lines need intact insulation and firm crimps to remain stable.
Reassembly and Post-Repair Tests
Restore power and run a service or diagnostic cycle if your model supports it; otherwise start a Normal cycle and observe fill, wash, and heat. The control should no longer post 3–2 / F3E2, and the heater should energize when the machine reaches the target temperature. After the first successful run, let the dishwasher cool and check the OWI area for leaks to confirm the new seal seated correctly.
Preventing a Repeat
Keep the sump area clean, fix any minor leaks promptly, and ensure the wiring sits in its clips so vibration doesn’t rub through insulation. Avoid aggressive spray from pressure cleaning near the toe-kick; water driven into the connector can create shorts that return as intermittent codes. Running a periodic high-temperature cycle with the correct detergent and rinse aid helps limit residue on the OWI lens and around the connector, which keeps the thermistor readings stable.