01 This Is Why Your Car’s Clutch Fluid Is Low • 02 Is It Bad to Drive Long Distances and Turn Off the Engine I… • 03 This Is How to Test a Throttle Position Sensor Without Spec… • 04 Understanding the 4-Pin Relay: Functions, Applications, and… • 05 Infotainment Evolution: From AM and FM to Touchscreen Conne… • 06 This is Why Ignoring Your Oxygen Sensor Could Cost You Thou… • 07 You Can Tell A Lot About A Car By Listening To Its Engine I… • 08 Signs Your Radiator is Clogged and How to Fix It Yourself • 09 This Is Why Your Car’s Engine Oil Turns Black So Fast • 10 What Depth of Water Can I Drive Through With My Car? •

DTC codes / Jaguar codes / P1375

P1375 · JaguarIgnition Coil Cylinder 5 Early Activation Fault

P1375 on a Jaguar indicates that the engine control module (ECM) has detected an early activation event on the ignition coil for cylinder 5, meaning the coil fired before the commanded spark timing or the feedback signal arrived earlier than expected. This is a manufacturer-specific fault that points to a problem within the cylinder 5 ignition coil circuit, the coil itself, or the wiring between the coil and the ECM.

SystemPowertrain
Code typeJaguar specific
SeverityMedium
Fix difficultyIntermediate
AreaIgnition system and misfire

Symptoms you may notice

  • Illuminated check engine light, often with no other noticeable symptoms
  • Rough idle or misfire sensation, especially when the engine is cold
  • Hesitation or stumble during acceleration
  • Reduced fuel economy due to incomplete combustion
  • In rare cases, a flashing check engine light if the misfire becomes severe

Common causes, most likely first

  1. Faulty ignition coil on cylinder 5 (internal short or degradation)
  2. Damaged or chafed wiring in the cylinder 5 coil circuit (power, ground, or control wire)
  3. Corroded or loose electrical connector at the cylinder 5 coil
  4. Failed spark plug or incorrect spark plug gap causing abnormal coil feedback
  5. ECM software glitch or internal driver fault for the cylinder 5 coil
  6. Electrical interference from aftermarket components or poor grounding

How to diagnose and fix it

  1. Verify the code with a Jaguar-compatible scan tool and check for any related misfire codes
  2. Inspect the cylinder 5 ignition coil connector and wiring for corrosion, damage, or loose pins
  3. Swap the cylinder 5 ignition coil with a known-good coil from another cylinder and see if the code moves
  4. Check the spark plug condition and gap on cylinder 5, replacing if worn or fouled
  5. Perform a resistance test on the cylinder 5 coil and compare with specifications
  6. Check for continuity and shorts in the coil control circuit between the coil and ECM
  7. If all electrical checks pass, reflash or replace the ECM as a last resort

Before you replace the ECM

  • A swapped coil that moves the code to another cylinder confirms the coil is at fault, but if the code stays on cylinder 5 the problem is in the wiring or ECM driver.
  • Early activation faults can be triggered by a failing spark plug that alters the coil's feedback signal, so always inspect plugs before condemning the coil.
  • Aftermarket ignition coils for Jaguars often have incorrect internal resistance and can set P1375 even when new, so use OEM-quality parts.
  • Poor engine ground connections can cause voltage spikes that mimic a coil fault, so check ground straps and battery terminals.
  • This code may appear intermittently and not set a misfire code until the fault worsens, so do not ignore it if the engine still runs smoothly.

Can I keep driving with P1375?

You can usually drive the car with P1375 set, but avoid heavy acceleration or sustained high speeds until the fault is repaired, as a worsening misfire can damage the catalytic converter. If the check engine light starts flashing, stop driving and seek service immediately.

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.

Running on fumes Free guides aren't free to make. Top up the tank. Any amount, one time. Fuel the Garage