What Does P1343 Mean?
P1343 indicates that the ignition coil power output stage 2 has a short circuit to ground. The ECU or ignition module driver transistor for coil 2 detects an abnormally low resistance path to ground on its control circuit. This prevents proper switching of the coil primary winding and results in no spark or weak spark on the cylinder controlled by coil 2.
Safety Warning
Persistent misfire on the affected cylinder reduces power and increases emissions. Unburned fuel reaching the catalytic converter can cause overheating and converter failure. Prolonged driving is not recommended.
Common Causes
30%
Damaged wiring between ECU and ignition coil 2 shorted to chassis ground
30%
Failed ignition coil 2 with internal short to ground
18%
Water or coolant intrusion in the coil 2 connector
12%
ECU ignition output stage 2 driver failure
10%
Coil 2 mounting bracket or bolt creating ground path through damaged insulation
Diagnostic Steps
1
Disconnect ignition coil 2 and clear the code. Crank or run the engine briefly to see if the code returns without the coil connected.
2
With the coil disconnected, measure resistance from the control wire at the ECU connector to chassis ground. A reading below several thousand ohms indicates a wiring short.
3
Inspect the coil 2 wiring harness along its entire run for damaged insulation, pinch points, or areas where it contacts metal components.
4
Check for moisture or corrosion in the coil 2 electrical connector. Dry and clean as needed.
5
Test ignition coil 2 primary and secondary resistance. Check insulation resistance from each terminal to the coil housing for internal short to ground.
6
If wiring and coil are verified good, test the ECU output stage by monitoring the drive signal characteristics.
Estimated Repair Cost
$100 - $450
Parts + labor, varies by vehicle and location
P1343 indicates that the ignition coil power output stage 2 has a short circuit to ground. The ECU or ignition module driver transistor for coil 2 detects an abnormally low resistance path to ground on its control circuit. This prevents proper switching of the coil primary winding and results in no ...
The most common cause of P1343 (Ignition Coil Power Output Stage 2 Short to Ground) is: Damaged wiring between ECU and ignition coil 2 shorted to chassis ground
Typical repair costs for P1343 range from $100 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Persistent misfire on the affected cylinder reduces power and increases emissions. Unburned fuel reaching the catalytic converter can cause overheating and converter failure. Prolonged driving is not recommended.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1343 to identify the root cause.
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Quick Info
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Powertrain
System
Ignition System
Difficulty
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