Chassis, generic

C0907 TPMS Sensor 4 Battery Low

Check engine lightUsually off
EmissionsNot relevant
Drive cycleRequired
Limp modeNo

C0907 has no public owner: code lists, the NHTSA index and the GM, Saab and Mitsubishi service indexes all lack it. Per its title it flags a fading battery in transmitter 4. How that state is noticed: the sensor measures its cell through a voltage divider and sends a battery byte with each pressure message, as a CM Automotive patent shows. Mitsubishi stores C1940 for tire 4 in this case; once the cell sags further, the receiver stops hearing the sensor and the same family sets C1941 after roughly 20 minutes of driving without its ID. The 2011 Saab 9-4X handles it per corner, subcode 03 under C0750 to C0765. The code thus heralds a coming loss of signal; replacing the sensor before that avoids a dark pressure display.

Likely causes

Transmitter cell weak from age
Cold weather pushing an ageing cell below the warning level
Fault in the sensor's voltage measurement

Symptoms

  • TPMS warning lamp with a sensor fault message
  • Later, dashes instead of a value for the affected wheel

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–200
Time0.5–1.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

tpms sensortpms receiver

Related codes

C0905C0900C0902C0953

References: mitsubishitechinfo.com, patents.google.com, saabwisonline.com.