P1373
Cylinder 7 Ignition Circuit Open.
- Volkswagen
- Powertrain
- Manufacturer code
- Medium severity
How this code is built
- P
- SystemPowertrain
- 1
- Defined byThe manufacturer
- 3
- AreaIgnition system or misfire
- 73
- FaultThe specific fault in that area
What it means
On Volkswagen, P1373 means the engine control unit has detected an open circuit in the ignition circuit for cylinder 7. It is only relevant to engines with at least seven cylinders, such as V8 or W12 units. The control unit saw no expected current or feedback in the ignition output stage for that cylinder, so it set the fault and may cut fuel or ignition to it.
Symptoms
- Engine misfire, rough running or shaking at idle
- Engine management light on, possibly flashing under load
- Loss of power and poor acceleration
- Hesitation or juddering when pulling away
- Raised fuel consumption
- Possible fuel smell or limp-home behaviour
Possible causes
- Faulty ignition coil on cylinder 7 with an open internal winding or failed driverlikely
- Damaged wiring, chafing or broken wire between the engine control unit and the cylinder 7 coillikely
- Corroded, loose or pushed-out connector terminals at the coil plug or control unitpossible
- Missing or poor power supply or earth to the coil circuit (fuse, relay or earth point, depending on model)possible
- Moisture or oil contamination in the coil connector or spark plug wellpossible
- Fault inside the engine control unit ignition output stagerare
How to diagnose
- Read all stored codes and freeze frame data, and note whether other cylinder misfire or ignition codes are present
- Check cylinder numbering for the specific engine, as the layout varies by model, and identify the cylinder 7 coil
- Inspect the coil connector, wiring and loom for chafing, heat damage, oil, water and bent or corroded terminals
- Check the fuse and the power supply and earth to the coil against the wiring diagram for that engine
- Swap the cylinder 7 coil with a known good cylinder and see whether the fault moves, then clear codes and retest
- Measure circuit continuity and resistance between the coil connector and control unit with the battery disconnected, following the wiring diagram
- Inspect the spark plug for that cylinder for wear, fouling or incorrect gap
- If the wiring, supply and coil all test good, have the control unit output checked before considering replacement
How to fix
- Replace the faulty cylinder 7 ignition coil
- Repair or replace damaged wiring or the affected section of the loom
- Clean, repair or replace corroded or loose connector terminals and fit the connector securely
- Restore the faulty supply, fuse or earth connection and find out why it failed
- Replace worn or fouled spark plugs, and fit the full set if they are due
- Repair or replace the engine control unit only when all other causes have been ruled out
Can I keep driving?
Medium severity
It can be driven short distances at gentle load, but a persistent misfire can overheat and damage the catalytic converter, so get it fixed soon. Stop driving if the warning light flashes or the engine runs very roughly.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.