OBD-II code · Powertrain (generic, extended)
P2506 ECM/PCM Power Input Signal Range/Performance
The switched-battery input to the ECM/PCM is present, but the level or transient behaviour is out of plausibility — sagging during cranking, slow ramp-up after main-relay close, or noisy. Often caused by aged main relay contacts or a weak battery feed under load.
Is it safe to drive with P2506?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyAged main relay contacts with rising contact resistance
- PossibleWeak battery sagging during crank
- Less likelySensor element aged beyond calibration window
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–2 h
- Emissions test
- Usually unaffected
- Parts involved
- Main Relay, Power Distribution, Battery Cables
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.