P2156
Fuel Injector Group D Supply Voltage Circuit Low
Fuel injector circuit
Generic OBD-II
High
What it means
P2156 means the ECM sees the supply voltage feeding fuel injector group "D" is lower than it should be. Injectors need full battery voltage to open reliably, so a low feed can leave the affected cylinders misfiring or dropping out, causing rough running, hesitation, or stalling until the circuit is repaired.
High
Can I keep driving? May run poorly or not at all — low supply voltage to an injector group can leave those cylinders misfiring, so expect rough running or stalling.
Common symptoms
What you'll notice
- Check-engine light on
- Misfire or rough running on the affected cylinder group
- Hard starting or stalling
- Reduced power and hesitation
Common causes
Most likely first
- High resistance or a partial short in the injector group's supply-voltage wiringLikely
- Corroded or loose connector dropping the supply voltageCommon
- Weak or faulty relay/fuse feeding the injector groupCommon
- Poor ground or a faulty fuel injector control moduleLess often
How to diagnose & fix
Work through it in order
- Do a visual inspection of the injector harness and connectors for corrosion, chafing, or loose pins.
- Measure the supply voltage at the injector group and compare it to battery voltage — a low reading points to resistance in the feed.
- Check the relay, fuse, and connections in the supply circuit.
- Verify the injector control module ground circuits against battery ground.
- Repair the high-resistance connection or replace the failed part, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P2156?+
Not really. Low supply voltage can cause the injector group to misfire, and prolonged misfiring risks catalytic-converter damage. Have it repaired promptly.
Can I just clear P2156?+
It clears, but the low-voltage condition returns as soon as the injectors run. Fix the wiring, connection, or component causing the voltage drop first.
Related codes
Often seen with P2156
Read & clear P2156 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