Chassis, generic

C0903 TPMS Sensor 2 Position Performance

Check engine lightUsually off
EmissionsNot relevant
Drive cycleRequired
Limp modeNo

Searches found C0903 neither in code lists nor in maker documents; a single NHTSA hit is a truck maker's campaign number. The title addresses locating transmitter 2 on the vehicle. Two methods are documented. A Ford patent puts a low frequency initiator into each wheel well: the controller fires it above about 20 mph, waits 3 seconds for the sensor to answer with its ID and a special status flag, raises the transmit power step by step and declares an error once the limit is reached without reply. A 2022 Mitsubishi system without initiators derives the position from the timing between the wheel speed sensors and each tire sensor. If either check ends without a clear match, the corner of sensor 2 stays unknown.

Likely causes

Location learning interrupted, e.g. short trips at low speed after tire service
Sensor does not answer the wheel well initiator (weak LF field, misaligned initiator)
Acceleration or rotation detection inside the sensor faulty

Symptoms

  • TPMS lamp on with all tires correctly inflated
  • Display shows pressures without assigning them to wheel positions

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–250
Time0.3–1.5 h

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

Parts involved

tpms sensortpms receiver

Related codes

C0901C0902C0912

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