OBD-II code · Powertrain (generic, extended)
P2303 Ignition Coil B Primary Control Circuit Low
The ECU reads a low primary control voltage on ignition coil B. Misfire is typically observed on the cylinder this coil serves.
Is it safe to drive with P2303?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyInternal coil short
- PossiblePrimary wire shorted to ground
- Less likelyConnector pins corroded - high contact resistance
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.2–1 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Ignition Coil, Coil Driver, Ignition Wiring
Related codes
- P2300Ignition Coil A Primary Control Circuit Low
- P2306Ignition Coil C Primary Control Circuit Low
- P2309Ignition Coil D Primary Control Circuit Low
- P2312Ignition Coil E Primary Control Circuit Low
- P2315Ignition Coil F Primary Control Circuit Low
- P2318Ignition Coil G Primary Control Circuit Low
- P2321Ignition Coil H Primary Control Circuit Low
- P2324Ignition Coil I Primary Control Circuit Low
- P2327Ignition Coil J Primary Control Circuit Low
- P2330Ignition Coil K Primary Control Circuit Low
- P2333Ignition Coil L Primary Control Circuit Low
- P2301Ignition Coil A Primary Control Circuit High
- P2302Ignition Coil A Secondary Circuit
- P2304Ignition Coil B Primary Control Circuit High
- P2305Ignition Coil B Secondary Circuit
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.