P2C45Battery Isolation/Voltage Stabilization Control Circuit Low
- Generic OBD-II code · Powertrain
- Can trigger limp mode
- How the car detects it
- P2C45 is stored when the line that commands the battery isolation or voltage stabilization switch reads lower than its commanded state allows, the classic picture of a short to ground or, with a high-side driver, an open coil pulling the sense voltage down. The switch exists so that the starter can draw its peak current from one battery while sensitive loads stay on a separate, stable supply; Ford's start-stop patent describes this split and notes that relays used for it wear and suffer from contact oxide. No manufacturer publishes P2C45 itself; Ford's PowerBoost F-150 cases are filed under P2C44. A chafed harness near the battery tray or a water-damaged connector is the usual find. Stop-start or engine pull-up support is typically blocked until the short is repaired.
- What you may notice
- Fault indicator on
- Stop-start function unavailable
- Possible blown fuse in the control circuit
- Likely causes
- LikelyControl wire chafed through and shorted to ground
- PossibleCorroded or water-damaged connector near the battery
- PossibleIsolator relay coil shorted internally
- Repair
- Medium · Usually a job for a workshop.Typical cost: €60 – €450
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.