P263AMIL Control Circuit Low
- Generic OBD-II code · Powertrain
- Matters for the ITP
- How the car detects it
- P263A means the engine module has found the line that switches the malfunction indicator lamp shorted to ground. GM checks it while the low-side driver is off: if the voltage stays low with an impedance to ground of about 0.5 ohm, the lamp control is faulty; the 2014 tables need 50 of 63 samples at 50 ms intervals, the 2019 tables a single sample, with run/crank voltage of at least 11 V and remote start inactive. GM files it as Type B but marks it no MIL, which makes sense because the lamp itself is the affected part; some controllers also log P0650. GM preliminary information PIT5391 lists P263A and P263B among codes left behind when ignition 1 voltage drops out through a KR73 relay or terminal fault on 2014–2016 trucks. A permanently lit lamp is the main symptom.
- What you may notice
- Engine warning lamp lit permanently
- Code stored even though the lamp cannot report it reliably
- Likely causes
- LikelyMIL control wire chafed and touching ground
- PossibleLoss of ignition 1 voltage via main relay or fuse block terminal
- RareFaulty lamp input in the instrument cluster
- Inspection (ITP)
- Can matter for the ITP: it concerns the emissions system.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €40 – €500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.