What Does P2304 Mean?
The PCM has detected an abnormally high voltage condition in the primary control circuit for ignition coil B. This indicates a problem with the driver circuit inside the PCM or an open circuit in the wiring between the PCM and the coil.
Common Causes
35%
Open circuit in primary control wire between PCM and coil B
30%
Failed ignition coil B with internal open circuit
20%
Corroded or damaged connector at coil B or PCM
15%
Failed PCM ignition coil driver circuit
Diagnostic Steps
1
Step 1: Perform visual inspection of ignition coil B connector and wiring for damage, corrosion, or loose connections
2
Step 2: Check resistance of primary winding in ignition coil B (typically 0.4-2 ohms) and compare to specifications
3
Step 3: Test continuity of control wire from PCM to ignition coil B connector
4
Step 4: Check for open circuit or high resistance in ground circuit for ignition coil B
5
Step 5: If all wiring and coil test good, suspect failed PCM driver circuit and consider PCM replacement
Estimated Repair Cost
$150 - $800
Parts + labor, varies by vehicle and location
The PCM has detected an abnormally high voltage condition in the primary control circuit for ignition coil B. This indicates a problem with the driver circuit inside the PCM or an open circuit in the wiring between the PCM and the coil.
The most common cause of P2304 (Ignition Coil "B" Primary Control Circuit High) is: Open circuit in primary control wire between PCM and coil B
Typical repair costs for P2304 range from $150 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle may experience severe misfires, rough running, or may not start. Can cause catalytic converter damage if driven for extended periods with misfire.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2304 to identify the root cause.
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Quick Info
Category
Powertrain
System
Ignition System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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