What Does P2303 Mean?
The primary ignition coil driver circuit for cylinder B (typically cylinder 2) is detecting voltage lower than expected. This indicates a short to ground or excessive current draw in the coil primary winding or control circuit.
Common Causes
40%
Shorted ignition coil B primary winding
30%
Wiring harness short to ground in coil B primary circuit
15%
Failed PCM ignition coil B driver circuit
10%
Corroded or damaged connector at coil B
5%
Moisture intrusion causing short in coil B circuit
Diagnostic Steps
1
Step 1: Disconnect ignition coil B connector and measure primary circuit resistance
2
Step 2: Check for short to ground in wiring between PCM and coil B using multimeter
3
Step 3: Test coil B primary resistance and compare to manufacturer specifications
4
Step 4: Swap coil B with another cylinder to determine if fault follows component
5
Step 5: Verify PCM coil B driver circuit output with oscilloscope if coil and wiring test good
Estimated Repair Cost
$100 - $500
Parts + labor, varies by vehicle and location
The primary ignition coil driver circuit for cylinder B (typically cylinder 2) is detecting voltage lower than expected. This indicates a short to ground or excessive current draw in the coil primary winding or control circuit.
The most common cause of P2303 (Ignition Coil "B" Primary Control Circuit Low) is: Shorted ignition coil B primary winding
Typical repair costs for P2303 range from $100 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle will likely misfire on cylinder B, causing rough running and potential catalytic converter damage. May experience reduced power and increased emissions.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2303 to identify the root cause.
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Quick Info
Category
Powertrain
System
Ignition System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
