01 The Oil Change Dilemma: Decoding the Importance of Time vs.… • 02 The Overlooked Car Part That Turns Every Drive Into A Fuel … • 03 Experts Warn Ignoring A Weak Ignition Coil Could Leave Your… • 04 Why Is My Engine Starts Fine When Cold But Hard to Start Wh… • 05 Common Car Starting Issues and How to Troubleshoot Them • 06 What to Do If Your Car Only Starts When You Hit the Starter • 07 System Too Lean: Causes, Symptoms, and Troubleshooting of a… • 08 Drivers Urged To Check Their Tires Immediately After Expert… • 09 WHAT IS AN ABS SENSOR? • 10 Why Manual Transmission Gear Shifts Are Not Simpler and in … •

DTC codes / GM codes / P1364

P1364 · GMIC Cylinder 4 Not Toggling After Enable

P1364 on a GM vehicle means the powertrain control module (PCM) commanded the ignition control (IC) circuit for cylinder 4 to switch states after enable, but the feedback voltage on that circuit never changed as expected. The PCM monitors the IC output and flags this code when cylinder 4 fails to toggle, indicating an open, shorted, or high-resistance fault in the circuit or a failed ignition coil/module driver.

SystemPowertrain
Code typeGM 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 felt as a shake or stumble, especially when cold
  • Reduced engine power or hesitation during acceleration
  • Slight decrease in fuel economy over time
  • In some cases, the engine may stall or be hard to start if the fault affects multiple cylinders

Common causes, most likely first

  1. Faulty ignition coil or ignition control module for cylinder 4
  2. Open or shorted wire in the IC circuit between the PCM and the coil/module
  3. Corroded or loose electrical connector at the coil, module, or PCM
  4. Failed PCM driver for the cylinder 4 IC circuit (rare but possible)
  5. Aftermarket alarm or remote start wiring tapped into the IC circuit causing interference
  6. Engine mechanical issue (e.g., bad spark plug, low compression) that prevents the coil from toggling correctly, though this is less common for a circuit-specific code

How to diagnose and fix it

  1. Scan all modules for stored and pending codes, and record freeze-frame data to confirm the fault conditions.
  2. Inspect the ignition coil and connector for cylinder 4 for corrosion, loose pins, or damaged wiring; repair or replace as needed.
  3. Use a digital multimeter to check resistance and continuity of the IC circuit from the PCM connector to the coil/module connector; compare to service information specifications.
  4. Swap the ignition coil from cylinder 4 with a known-good coil from another cylinder and clear the code; if the misfire moves, the coil is faulty.
  5. Check for aftermarket accessories wired into the IC circuit and remove or repair any splices that could cause interference.
  6. If the circuit and coil test good, perform a wiggle test on the harness while monitoring the IC circuit with a lab scope or scan tool to detect intermittent opens.
  7. As a last resort, verify PCM operation by checking for proper driver output on the IC circuit with a scope; replace the PCM only if all other possibilities are ruled out.

Why cylinder 4 IC codes get misdiagnosed

  • A P1364 can be set by a faulty ignition coil that still fires but has a degraded driver circuit, so a simple spark test may not reveal the problem.
  • Corrosion inside the coil connector boot is a common cause that is easily overlooked during visual inspection because the pins look clean from the outside.
  • The PCM may set this code only after the engine reaches a certain temperature or run time, so intermittent faults often require a test drive with a scan tool recording live data.
  • Aftermarket remote starters or alarm systems that tap into ignition wiring can back-feed the IC circuit and cause false toggling codes, especially if the installation was poorly done.
  • A weak battery or poor ground connection can cause voltage spikes that mimic a failed IC driver, so always check charging system and grounds before condemning the PCM.

Can I keep driving with P1364?

You can usually drive the vehicle short distances to a repair shop, but avoid heavy acceleration or towing because a persistent misfire can overheat the catalytic converter. If the check engine light is flashing or the engine runs very rough, stop driving and have it towed to prevent damage.

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 GM 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