P058A code meaning
Battery Monitor Module Performance
Powertrain system Generic code P05xx codes Check engine light
What P058A means
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. P058A means the module reports an internal fault of its own over LIN. GM checks it every 250 ms above 9 V, without LIN faults and at outside temperatures of −20 to 50 °C. Battery data are then unreliable – stop-start is blocked and the alternator usually runs a fixed substitute voltage. Loss of communication is a separate U code.
P058A at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 1 hours
- Clears after repairAfter a drive cycle
Symptoms of P058A
- Check engine light on
- Stop-start not available
- No driveability problems
Common causes of P058A
- Most likelyBattery sensor faulty internally
- PossiblePoor supply or ground at the sensor (loose terminal, corroded connector)
- PossibleSensor not relearned after battery replacement or disconnection
- Less likelyModule or engine module software
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Battery monitor moduleBattery terminalLin busEngine control module
What each part of P058A means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 5 | Area: vehicle speed, idle control and auxiliary inputs. |
| 8A | The exact fault in that area. |
What to do next
- Note P058A and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P058A
What does P058A mean?
P058A means "Battery Monitor Module Performance". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P058A?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P058A fail an emissions test?
Yes, it can. P058A is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P058A to fix?
Difficulty: easy. A typical repair takes 0.3 to 1 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P058A clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.