P058BBattery Monitor Module Current Monitoring Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- The battery monitor module (intelligent battery sensor) sits on the negative terminal of the 12 V battery: a shunt measures current, electronics also measure voltage and temperature and calculate state of charge, health and cranking ability, reporting over LIN. Energy management uses the data for alternator control, idle boost and stop-start release, which is why the engine module diagnoses it. GM sets P058A–P058F in its engine modules from 2016 as type B, warning lamp after two trips. P058B concerns current measurement. In the sensor variant the module itself reports implausible current; GM's eAssist and stop-start engines compare it with their own reference and set it at 22 A difference in 160 of 200 samples. GM bulletins for the 2014–16 Malibu and Impala name a ground ring lying on the sensor's shunt or a loose terminal – current then bypasses the shunt.
- What you may notice
- Check engine light, often sporadic
- Stop-start inactive
- Wrong state of charge display or battery warning
- Likely causes
- LikelyGround ring touching the shunt or loose
- PossibleFretting corrosion in the sensor connector, loose ground splice
- PossibleBattery sensor faulty
- RareRetrofitted loads grounded directly at the negative post
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Often possible to do yourself.Typical cost: €0 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.