What Does P2305 Mean?
The PCM has detected a fault in the secondary (high voltage) circuit of ignition coil B. This typically indicates weak spark, spark leakage, or an open secondary winding in the coil.
Common Causes
40%
Failed ignition coil B with shorted or open secondary winding
25%
Carbon tracking or spark leakage on coil B tower or boot
20%
Damaged or fouled spark plug in cylinder B
15%
Excessive secondary circuit resistance due to worn spark plug or high resistance plug wire
Diagnostic Steps
1
Step 1: Inspect ignition coil B for signs of carbon tracking, cracks, or oil contamination on the tower and boot
2
Step 2: Remove and inspect spark plug for excessive wear, incorrect gap, or fouling
3
Step 3: Test secondary winding resistance in ignition coil B (typically 6,000-15,000 ohms) and compare to specifications
4
Step 4: Perform spark test using spark tester to verify adequate spark intensity and color
5
Step 5: Replace ignition coil B if secondary circuit tests fail or visual damage is present
Estimated Repair Cost
$120 - $350
Parts + labor, varies by vehicle and location
The PCM has detected a fault in the secondary (high voltage) circuit of ignition coil B. This typically indicates weak spark, spark leakage, or an open secondary winding in the coil.
The most common cause of P2305 (Ignition Coil "B" Secondary Circuit) is: Failed ignition coil B with shorted or open secondary winding
Typical repair costs for P2305 range from $120 to $350, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Cylinder misfire will cause rough idle, reduced power, and poor fuel economy. Extended driving with misfire can damage catalytic converter.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2305 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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