P2D58 code meaning
Generator B Mechanical Performance
What P2D58 means
P2D58 reports that generator B, the second alternator of a dual charging system, does not deliver as commanded for mechanical reasons, most often because its drive slips. Such machines often sit on their own belt and idler. GM's customer satisfaction program N192255140 for 2019 Silverado medium-duty trucks with secondary generator option KHB shows how sensitive that mounting is: a bolt that missed its clamp load could work loose, so dealers fitted a new bracket for the A/C compressor together with the idler and inspected the belt. No manufacturer documents P2D58 publicly. Infineon's LIN regulator TLE8881-3 recognises a broken belt or stalled alternator when the phase signal stops swinging above a cut-in speed. Check belt, tensioner, pulley and bearings first. Generator A: P065C.
P2D58 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyEasy, DIY possible
- Typical labor0.5 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2D58
- Charge warning lamp, low charging voltage
- Belt squeal or noise from the second alternator
Common causes of P2D58
- Most likelyWorn, glazed or oil-soaked drive belt slipping
- PossibleWeak tensioner or loose idler pulley mounting
- PossibleStiff alternator bearing or faulty overrunning pulley
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Generator bDrive beltBelt tensioner
What each part of P2D58 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 58 | The exact fault in that area. |
What to do next
- Note P2D58 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 P2D58
What does P2D58 mean?
P2D58 means "Generator B Mechanical Performance". P2D58 reports that generator B, the second alternator of a dual charging system, does not deliver as commanded for mechanical reasons, most often because its drive slips. It is a generic code, so it means the same on every make.
Is it safe to drive with P2D58?
P2D58 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will P2D58 fail an emissions test?
P2D58 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is P2D58 to fix?
Difficulty: easy. A typical repair takes 0.5 to 2.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P2D58 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.