Panasonic mini split error code H17

Common causes

• The outdoor suction temperature thermistor has failed (they do drift and fail with age and heat cycling).
• Its plug has worked loose from the control board, or a pin has corroded.
• The sensor lead is chafed, pinched or chewed, giving an intermittent open or short.
• The control board's sensor input has failed (rare compared with the sensor itself).

How to fix it yourself

Work through the checks below first; they resolve most cases. If they do not, the repair itself may need a technician.

1. Reset the system: switch the breaker (or the outdoor disconnect) off, wait a full five minutes so the boards fully discharge, then switch it back on and restart from the remote.
2. If the code comes straight back after a reset, the fault is real and not a glitch.
3. With power off, locate the outdoor suction temperature sensor on the larger (suction) line near the compressor inlet. Follow its lead back to the board and reseat the plug firmly.
4. Inspect the lead for damage along its whole length, especially where it passes through the chassis.
5. If you have a multimeter, unplug the sensor and measure its resistance. A reading near zero ohms (short) or infinite (open) confirms a bad sensor. Most mini split thermistors read roughly 5 to 20 kΩ at room temperature, so a value in that range with a steady drift as you warm it in your hand means the sensor is fine and the board is the suspect.
6. Replacement thermistors are inexpensive and plug in. Match the part number from the parts list for your model.

Switch off power at the breaker before opening either unit. Capacitors in the outdoor unit hold a charge for several minutes after power is cut.

When to call a technician

Sensor swaps are a doable DIY job on most units. Call a technician if the sensor tests good and the code persists, because that points at the control board.

Which Panasonic units show H17

This page applies to Panasonic Exterios, ClimaPure and Multi-zone (CU-xE) units. Panasonic's own documentation lists H17 as "Outdoor suction temperature sensor fault (open or short circuit)", the same definition used across the Panasonic it is built on. If your unit shows a code with a different shape (for example a four-character code, or a plain number), it is from a different table; use the lookup with your exact code.

Where Panasonic shows this code

The indoor unit blinks its Timer lamp when a fault is stored. To read the code, point the remote at the unit and hold the CHECK button (on the back of the remote, under the flap on most models) for about 5 seconds until -- shows, then press the temperature up or down button; each press shows a code, and the unit beeps continuously (not a short beep) when the code shown is the stored fault. H codes are faults (a sensor, motor or board that needs attention). F codes are protections: the outdoor unit stopped itself because of pressure, temperature or current.

Other Panasonic codes

Same part of the system as H17:

All Panasonic error codes