C0669 Right Rear Wheel Speed Sensor B Circuit High
With C0669 the second right rear speed channel shows a level above the valid range, which usually means it is connected to a voltage source it should not see. No carmaker publishes this code. Sensor chips are built to survive such faults for a while: NXP builds the input die of the KMI25 with a process rated for high voltage, precisely to shield the measuring parts from the harsh conditions on the supply line. For the older KMI15 NXP recommends extra parts against voltage spikes and reverse polarity and notes that many vehicle networks already cap load-dump surges at about 40 V. The brake module, however, will not accept the reading and shuts the channel off until the short to battery, the damaged lead or the faulty sensor has been dealt with.
Likely causes
Symptoms
- Warning lamp right after switching on
- Channel B switched off, assistance functions reduced
Repair estimate
Typical range across vehicles; the real cost depends on what the testing finds.