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DTC codes / Jaguar codes / P1372

P1372 · JaguarIgnition Coil Cylinder 2 Early Activation Fault

P1372 on a Jaguar indicates that the engine control module (ECM) has detected an early activation fault for the ignition coil serving cylinder 2, meaning the coil fired before the commanded spark timing or the feedback signal arrived outside the expected window. The ECM monitors coil primary current and ionization feedback to flag this fault when the coil's activation does not match the commanded dwell and timing.

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 cold
  • Hesitation or stumble during acceleration
  • Reduced engine power or limp mode in severe cases
  • Slightly elevated fuel consumption due to incomplete combustion
  • Intermittent misfire that may not be present at all times

Common causes, most likely first

  1. Faulty ignition coil on cylinder 2 (internal short or degraded insulation)
  2. Worn or contaminated spark plug on cylinder 2 causing abnormal ionization feedback
  3. Damaged or corroded wiring harness connector at the cylinder 2 coil
  4. Chafed or open circuit in the coil trigger or feedback wire
  5. Poor engine ground connection affecting coil operation
  6. ECM software glitch or internal driver fault (less common)
  7. Aftermarket coil with incorrect electrical characteristics

How to diagnose and fix it

  1. Inspect the cylinder 2 ignition coil connector and wiring for corrosion, looseness, or damage
  2. Swap the cylinder 2 ignition coil with a known-good coil from another cylinder and see if the fault moves
  3. Remove and inspect the spark plug on cylinder 2 for wear, fouling, or incorrect gap; replace if necessary
  4. Check coil primary and secondary resistance with a multimeter and compare to specifications
  5. Perform a wiggle test on the coil harness while monitoring misfire counters or the P1372 status
  6. Verify engine ground straps are clean and tight
  7. If all else checks out, reprogram or replace the ECM as a last resort

Before you replace the ignition coil

  • A spark plug with excessive gap or carbon fouling can mimic a coil fault by altering the ionization signal the ECM uses to detect early activation.
  • Corroded pins in the coil connector are a frequent cause on older Jaguars, especially where the harness routes near heat sources.
  • Swapping the coil to another cylinder is the quickest way to confirm whether the fault follows the coil or stays with cylinder 2.
  • The ECM may set P1372 intermittently due to a marginal coil that only misbehaves when hot or under load, so a cold static test can miss it.
  • Aftermarket coils with incorrect dwell characteristics can trigger this code even when they seem to work fine otherwise.

Can I keep driving with P1372?

You can usually drive the car short distances at moderate speed, but avoid heavy acceleration or sustained high-load driving until the fault is repaired. Prolonged driving with a misfire can damage the catalytic converter and cause further engine problems.

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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