P1237–P1244 Cylinder 1 Fuel Injector (N30) Circuit - Open Circuit
The circuit is broken somewhere - a cut wire, a corroded pin or an unplugged connector means the signal never arrives.
Can you drive it? This class of fault can cause real mechanical damage if you keep driving on it. A persistent misfire also destroys the catalytic converter, which is the expensive part.
Which code is which
Same fault, different cylinder or bank — diagnosed the same way. Several set together usually means one shared cause.
| Code | Definition | Severity |
|---|---|---|
P1237 | Cylinder 1 Fuel Injector (N30) Circuit - Open Circuit | Do not keep driving |
P1238 | Cylinder 2 Fuel Injector (N31) Circuit - Open Circuit | Do not keep driving |
P1239 | Cylinder 3 Fuel Injector (N32) Circuit - Open Circuit | Do not keep driving |
P1240 | Cylinder 4 Fuel Injector (N33) Circuit - Open Circuit | Do not keep driving |
P1241 | Cylinder 5 Fuel Injector (N83) Circuit - Open Circuit | Do not keep driving |
P1242 | Cylinder 6 Fuel Injector (N84) Circuit - Open Circuit | Do not keep driving |
P1243 | Cylinder 7 Fuel Injector (N85) Circuit - Open Circuit | Do not keep driving |
P1244 | Cylinder 8 Fuel Injector (N86) Circuit - Open Circuit | Do not keep driving |
The definition
P1237: Cylinder 1 Fuel Injector (N30) Circuit - Open Circuit.
P1237 is a manufacturer-specific powertrain code (the engine or gearbox). Its meaning is set by the carmaker rather than by the SAE standard, so a generic OBD-II reader will often show it as an unknown code or misread it.
What to check first
Cheapest and fastest checks first:
- Check the connector is fully seated and the locking tab is engaged. A half-seated plug is the single most common cause of an open circuit.
- Back-probe the pins and check continuity from the part back to the module connector.
- Inspect for a pushed-back or corroded terminal - the wire looks fine but the pin has backed out of the housing.
Reading the code is the easy part
A code names the circuit that complained. What tells you why is watching the sensor behind it while the engine runs — and that is where a code reader stops and a diagnostic tool starts.
VAGPULSE reads every module in a VW, Audi, Skoda or SEAT — not just the engine — shows the live measuring blocks behind this fault, gives you the freeze-frame conditions it was logged under, and clears it once you have fixed it. It also does what a generic OBD reader cannot on a VAG: service resets, coding, adaptations, and Stage 1–3 flashing with your original file saved first.
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Common questions
What does P1237 mean?
P1237 means Cylinder 1 Fuel Injector (N30) Circuit - Open Circuit. The circuit is broken somewhere - a cut wire, a corroded pin or an unplugged connector means the signal never arrives.
Can I drive with P1237?
This class of fault can cause real mechanical damage if you keep driving on it. A persistent misfire also destroys the catalytic converter, which is the expensive part.