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DTC codes / Jaguar codes / P1205

P1205 · JaguarCylinder 5 Injector Circuit Open/Shorted

P1205 on a Jaguar indicates that the engine control module (ECM) has detected an open circuit or a short to ground or power in the electrical path for cylinder 5's fuel injector. The ECM monitors injector current and voltage; when the expected electrical signature is missing or out of range, it flags this fault and may disable that injector to protect the driver circuitry.

SystemPowertrain
Code typeJaguar specific
SeverityMedium
Fix difficultyIntermediate
AreaFuel and air metering (injector circuits)

Symptoms you may notice

  • Illuminated check engine light, often with no other noticeable symptoms
  • Rough idle or misfire that is most pronounced when the engine is cold
  • Noticeable loss of power and hesitation during acceleration
  • Increased fuel consumption due to incomplete combustion in cylinder 5
  • In severe cases, the engine may enter limp mode or run very poorly
  • A faint fuel odor from the exhaust if the injector is stuck open or closed

Common causes, most likely first

  1. Failed cylinder 5 fuel injector (open coil or shorted winding)
  2. Damaged or corroded electrical connector at the cylinder 5 injector
  3. Chafed, broken, or shorted wire in the injector harness near the cylinder head
  4. Faulty engine control module (ECM) injector driver circuit
  5. High resistance in the injector ground circuit or poor engine ground
  6. Internal short in the injector caused by contamination or overheating
  7. Aftermarket or incorrectly installed injector with wrong resistance

How to diagnose and fix it

  1. Perform a visual inspection of the cylinder 5 injector connector and harness for damage, corrosion, or loose pins
  2. Measure the resistance of the cylinder 5 injector with a multimeter and compare to the manufacturer's specification
  3. Check for battery voltage at the injector connector with the key on and engine off, using a noid light or multimeter
  4. Test the injector control circuit from the ECM to the injector for continuity and short to ground/power
  5. Swap the cylinder 5 injector with a known-good injector from another cylinder to see if the fault moves
  6. If the injector is faulty, replace it and clear the code, then verify the repair with a road test
  7. If the wiring or ECM driver is faulty, repair the harness or replace/program the ECM as needed

Before you replace the cylinder 5 injector

  • A P1205 can be set by a simple loose connector that only loses contact when the engine is hot, so always wiggle-test the harness while watching live injector data.
  • Jaguar's injector drivers are sensitive to resistance changes; a replacement injector with the wrong part number or resistance can trigger the same code even if it physically fits.
  • The code does not always mean the injector itself has failed; a shorted wire in the harness near the exhaust manifold is a common cause on older Jaguar V8s.
  • If the ECM driver is damaged, it often affects only one injector, but a failed driver can also cause a no-start condition that is misdiagnosed as a faulty injector.
  • Always check for related misfire codes like P0305; if P0305 is present along with P1205, the injector circuit is the primary suspect, but if only P1205 is stored, the fault may be intermittent.

Can I keep driving with P1205?

You can drive the vehicle short distances to a repair shop, but avoid heavy acceleration or sustained high speeds because a misfiring cylinder can overheat the catalytic converter and cause costly damage. If the engine is running very rough or flashing the check engine light, stop driving and have it towed.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

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

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