E17 displayed, unit reports a sensor open circuit.

Safety: Turn off power before opening the unit.

Steps:

• Check plug connection: Ensure that the sensor plug is fully seated on the PCB header.
• Continuity test: With the sensor unplugged, measure resistance across its leads. Infinite resistance indicates a broken sensor; replace it.
• Check for breaks: Flex the cable gently while measuring; intermittent readings suggest an internal break in the cable.

Note: Always route replacement sensor cables away from sharp edges and hot surfaces to prevent future failures.