Failed fuel injector on cylinder 6 (open internal coil); Damaged or corroded electrical connector at the cylinder 6 injector; Broken, chafed, or shorted wire in the injector harness near the cylinder 6 injector; Faulty engine control module (ECM) injector driver circuit (less common); Rodent damage to the injector wiring harness; Loose or damaged ground connection for the injector circuit

DTC codes / Volkswagen codes / P1242

P1242 · VolkswagenCylinder 6 Injector Circuit Open Circuit

Q: What does code P1242 mean?

Cylinder 6 Injector Circuit Open Circuit. P1242 on Volkswagen vehicles indicates that the engine control module (ECM) has detected an open circuit in the electrical path for the number 6 cylinder fuel injector. The ECM commands the injector to fire but sees no current flow or an unexpected voltage drop, which it interprets as a break in the wiring or a failed injector coil.

P1242 on Volkswagen vehicles indicates that the engine control module (ECM) has detected an open circuit in the electrical path for the number 6 cylinder fuel injector. The ECM commands the injector to fire but sees no current flow or an unexpected voltage drop, which it interprets as a break in the wiring or a failed injector coil.

SystemPowertrain

Code typeVolkswagen specific

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering (injector circuits)

Symptoms you may notice

Check engine light illuminated, often with no other noticeable symptoms
Rough idle or misfire that may be more pronounced when the engine is cold
Noticeable loss of power and reduced fuel economy due to a dead cylinder
Engine may shake or vibrate, especially under acceleration or load
In some cases, the ECM may enter limp mode and limit engine speed

Common causes, most likely first

Failed fuel injector on cylinder 6 (open internal coil)
Damaged or corroded electrical connector at the cylinder 6 injector
Broken, chafed, or shorted wire in the injector harness near the cylinder 6 injector
Faulty engine control module (ECM) injector driver circuit (less common)
Rodent damage to the injector wiring harness
Loose or damaged ground connection for the injector circuit

How to diagnose and fix it

Perform a visual inspection of the cylinder 6 injector connector and wiring for damage or corrosion
Use a noid light or oscilloscope to check for a pulse at the injector connector while cranking the engine
Measure the resistance of the cylinder 6 injector with a multimeter and compare to the manufacturer's specification
Check continuity and resistance of the injector circuit from the ECM connector to the injector connector
If the injector fails the resistance test, replace the cylinder 6 fuel injector
If the wiring is faulty, repair or replace the affected section of the harness
Clear the fault codes and verify the repair with a test drive, ensuring the code does not return

Don't overlook the injector harness connector

A common cause of P1242 that is often missed is a loose or corroded connector at the cylinder 6 injector, which can mimic a failed injector and lead to unnecessary replacement.
The code does not always mean the injector itself has failed; wiring damage from heat, vibration, or rodent activity is a frequent culprit on higher-mileage Volkswagen engines.
Technicians sometimes replace the injector only to find the open circuit is in the harness, so always perform a continuity test before condemning the injector.
On some Volkswagen models, a faulty ECM driver can set this code, but this is rare and should only be suspected after all other possibilities are ruled out.
Related codes such as P0306 (cylinder 6 misfire) may be stored alongside P1242, and ignoring the injector circuit fault can lead to catalytic converter damage over time.

Can I keep driving with P1242?

Driving with P1242 is possible but not recommended for extended periods because the dead cylinder can cause misfire, increased fuel consumption, and potential damage to the catalytic converter. Avoid heavy acceleration and have the fault diagnosed promptly to prevent further issues.

Tools that help

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Guidance is general and written for Volkswagen vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.