What Does P1342 Mean?
P1342 indicates that the ignition coil power output stage 1 has a short circuit to battery positive (B+). The coil driver circuit has an unintended connection to a voltage source, which can keep the coil primary energized continuously, causing coil overheating and preventing normal spark generation. This fault will cause a complete misfire on the cylinder served by coil 1.
Safety Warning
A short to B+ on the coil driver can overheat the ignition coil, creating a fire risk. It also causes a complete misfire on the affected cylinder and may damage the ECU driver stage. Repair immediately.
Common Causes
30%
Wiring harness short to battery voltage from chafed insulation near a power circuit
30%
Failed ignition coil 1 with internal short to B+ supply
18%
Connector pin back-out or cross-pin contact in the coil connector
12%
Damaged ECU coil driver output pulling to B+
10%
Aftermarket wiring modification creating a short to power
Diagnostic Steps
1
Disconnect ignition coil 1 and measure voltage on the coil control wire at the harness side. With the coil disconnected and key on, no voltage should be present on the ECU drive line.
2
If voltage is found, trace the harness from the ECU to the coil looking for spots where the control wire may contact a power wire or fused circuit.
3
Inspect the coil connector for pushed-back pins, crossed terminals, or signs of heat damage from sustained current flow.
4
Measure ignition coil 1 primary resistance. A very low or zero reading indicates an internal short.
5
Check for any recent repairs or aftermarket wiring near the ignition coil harness that may have introduced a short.
6
Clear codes after repair and monitor for recurrence. Verify proper coil operation with an oscilloscope ignition pattern test.
Estimated Repair Cost
$100 - $500
Parts + labor, varies by vehicle and location
P1342 indicates that the ignition coil power output stage 1 has a short circuit to battery positive (B+). The coil driver circuit has an unintended connection to a voltage source, which can keep the coil primary energized continuously, causing coil overheating and preventing normal spark generation....
The most common cause of P1342 (Ignition Coil Power Output Stage 1 Short to B+) is: Wiring harness short to battery voltage from chafed insulation near a power circuit
Typical repair costs for P1342 range from $100 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A short to B+ on the coil driver can overheat the ignition coil, creating a fire risk. It also causes a complete misfire on the affected cylinder and may damage the ECU driver stage. Repair immediately.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1342 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Powertrain
System
Ignition System
Difficulty
Type
Manufacturer
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
