P2670Actuator Supply Voltage B Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2670 is set when the second high-side actuator supply delivers too little voltage while it is switched on, which nearly always means a short to ground somewhere on the supply line or in a load connected to it. GM documents it in several controllers. In the 16OBDG08 TCM tables for Silverado and Sierra a ground short is recognised at an impedance of 0.43 ohm or less, confirmed after three events, Type A. GM's 2023 TCM compares the supply voltage with battery voltage and also watches the average current, 60 ms to fail, Type A. In GM's hybrid tables (Volt THPC in 16OBDG01, HPC1 in 19OBDG01) high side driver 2 reports the short within about 0.13 s, again Type A after one trip. Solenoids on that supply drop out, so the transmission enters a failsafe mode.
- What you may notice
- Failsafe gear, no normal shifting
- MIL on immediately
- Further solenoid circuit codes stored alongside
- Likely causes
- LikelySupply wire chafed and shorted to ground
- PossibleShorted solenoid on the supplied group pulling the line down
- RareFaulty high-side driver in the controller
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.