What does it mean?
C1724 is a Chassis (ABS, traction control, steering) fault code. It indicates: Battery Voltage of LF Transmitter Drops. .
Symptoms
- Tyre pressure lamp flashing for about a minute at start-up and then staying on, indicating a system fault rather than low pressure
- Pressure value for the left front corner missing, frozen or appearing only occasionally
- Warning appearing in cold weather and behaving better once the car is warm
- No actual pressure problem found when the tyres are checked with a gauge
- Code returning even after the tyres are correctly inflated and a relearn is performed
Likely causes
- Sealed lithium cell inside the left front sensor reaching the end of its service life after years of transmitting
- Sensor kept transmitting more often than normal because of a stuck internal wake-up or motion circuit
- Repeated extreme heat from front brake temperatures accelerating cell discharge
- Moisture or liquid tyre sealant inside the tyre attacking the sensor electronics
- Sensor body cracked or the electronics damaged during a tyre change
- A used or aftermarket sensor fitted with an already depleted cell
- Weak transmission reaching the receiver so the module interprets the signal as a flat battery
How to fix it
- Read TPMS live data and compare signal status and battery status of all four sensors
- Trigger each sensor with a TPMS tool and see whether the left front responds at all
- Confirm the sensor ID stored for the left front position matches the sensor actually fitted
- With the tyre off the rim, check for sealant residue, water or physical damage around the sensor
- The cell is sealed inside the housing, so a low battery sensor must be replaced with a unit of the correct frequency and type
- Program the new sensor ID and run the position relearn, then confirm all four corners report
- Because sensors age together, check the remaining three and plan replacement if they are the same age