P068B
ECM/PCM Power Relay De-Energized Performance - Too Late
ECM power supply
Generic OBD-II
High
What it means
P068B means the main ECM/PCM power relay is dropping out later than expected after key-off — the relay stays energized too long. The most common cause is a worn or sticking relay. Left unaddressed, a slow-releasing main relay can keep modules powered and drain the battery, and an intermittent relay can cause occasional stalls or hard starts.
High
Can I keep driving? Usually yes, but a main relay that drops out too late can drain the battery or cause occasional stalling or hard starts — have it checked soon.
Common symptoms
What you'll notice
- Check-engine light on
- Battery drain or the system staying powered after key-off
- Occasional hard start or stall if the relay is intermittent
- Other stored codes from momentary power interruptions
Common causes
Most likely first
- Faulty ECM/PCM power relay with sticking or slow-releasing contactsLikely
- Poor or corroded connection at the relay socketCommon
- Damaged or shorted relay control wiringCommon
- ECM/PCM relay-control driver faultLess often
How to diagnose & fix
Work through it in order
- Scan and read freeze-frame to confirm the relay-timing fault.
- Swap or bench-test the ECM/PCM power relay, or substitute a known-good relay.
- Inspect the relay socket and control wiring for corrosion, backed-out pins, or shorts.
- Check the ECM power and ground feeds; if wiring and relay are good, suspect the ECM driver. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P068B?+
Usually yes, but a main power relay that releases too late can leave modules powered and drain the battery, or cause the odd stall, so repair it soon.
Can I just clear P068B?+
You can, but it returns if the relay or its circuit still holds power too long after key-off.
Related codes
Often seen with P068B
Read & clear P068B yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX