What does it mean?
P1373 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Ignition coil/amplifier, cylinder 7 - open circuit . This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms
- MIL on, flashing when the misfire becomes severe
- Rough idle, shaking and misfire especially under load
- Noticeable loss of power and hesitation when accelerating
- Higher fuel consumption and a raw fuel smell from the exhaust
- Popping or puffing from the exhaust, the engine running on fewer cylinders
Likely causes
- Broken or open primary control wire between the module and the coil
- Corroded, loose or backed-out terminal in the coil connector
- Ignition coil with an internally open primary winding
- Missing battery feed to that coil: a blown fuse or a faulty ignition relay
- Water or oil intrusion in the coil well and boot area
- Failed ignition amplifier or driver output stage
- Heat or rodent damage to the harness near the exhaust side of the engine
How to fix it
- Confirm which physical cylinder is number 7 on that engine layout before starting work
- Swap the coil with a neighbouring cylinder and see whether the fault follows the part
- Inspect the coil connector, boot and coil well for corrosion, melted plastic, oil and water
- Measure the coil primary resistance and check for battery voltage on the feed terminal with the ignition on
- Test continuity of the control wire from the coil back to the module to locate the open circuit
- Check the driver output with a logic probe or a scope while cranking
- Replace the coil or repair the harness, then inspect that cylinder's spark plug before refitting