What Does P1393 Mean?
The engine control module has detected an electrical fault in the power output stage (driver circuit) for ignition coil #1. This indicates a problem with the switching circuit that controls current flow to the primary coil winding.
Common Causes
40%
Failed ignition coil #1 with internal short or open circuit
25%
Damaged wiring or connector between ECM and ignition coil
15%
Failed ECM ignition driver transistor or output stage
12%
Corroded or loose connector pins at coil or ECM
8%
Short circuit in spark plug or excessive carbon tracking on coil
Diagnostic Steps
1
Step 1: Check for spark at cylinder #1; perform spark test using spark tester
2
Step 2: Measure primary and secondary resistance of ignition coil #1 according to specifications
3
Step 3: Inspect coil connector and wiring for damage, melting, or corrosion
4
Step 4: Test trigger signal from ECM to coil using oscilloscope or test light while cranking
5
Step 5: Swap coil #1 with another cylinder to determine if fault follows coil or stays with circuit
Estimated Repair Cost
$100 - $800
Parts + labor, varies by vehicle and location
The engine control module has detected an electrical fault in the power output stage (driver circuit) for ignition coil #1. This indicates a problem with the switching circuit that controls current flow to the primary coil winding.
The most common cause of P1393 (Ignition Coil Power Output Stage 1 Electrical Malfunction) is: Failed ignition coil #1 with internal short or open circuit
Typical repair costs for P1393 range from $100 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle may experience cylinder misfire, rough running, and reduced power. Safe to drive short distances but continued operation may 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 P1393 to identify the root cause.
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Quick Info
Category
Powertrain
System
Ignition System
Difficulty
Type
Manufacturer
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