P045C
EGR B Control Circuit Low
Exhaust gas recirculation (EGR)
Generic OBD-II
Medium
What it means
P045C means the ECM has seen an abnormally low voltage on the control circuit for the "B" EGR valve — typically a short to ground or an open in the wiring or solenoid. It's an emissions-system fault: the engine still starts and drives, but the EGR valve may not move as commanded, which can cause pinging or rough running under load.
Medium
Can I keep driving? Usually drivable — the engine runs, but you may notice a check-engine light and rough running or pinging under load until repaired.
Common symptoms
What you'll notice
- Check-engine light on
- Pinging or knocking under load
- Rough idle or slight hesitation
- Often no obvious drivability change
Common causes
Most likely first
- Short to ground or open in the EGR 'B' control circuit wiringLikely
- Failed EGR control solenoid or actuatorCommon
- Loose or corroded connector at the EGR valveCommon
- Carbon buildup binding the EGR valveLess often
- Rarely, a failed ECM driverLess often
How to diagnose & fix
Work through it in order
- Inspect the EGR 'B' valve connector and wiring for damage, shorts to ground, or corrosion.
- Measure the control circuit resistance and check for a low/grounded signal against spec.
- Test the EGR solenoid/actuator; replace it if the winding is out of range.
- Clean carbon from the EGR valve and passages, then clear the code and re-test.
FAQ
Quick answers
Is it safe to drive with P045C?+
Short-term yes, but a malfunctioning EGR can cause pinging under load, so have it repaired before long or heavy driving.
Can I just clear P045C?+
It will come back on the next drive cycle unless the wiring, solenoid, or valve fault is actually fixed.
Related codes
Often seen with P045C
Read & clear P045C 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