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DTC codes / P03xx · Ignition system and misfire / P036E

P036EIgnition H Control Signal Circuit Low

P036E indicates that the powertrain control module (PCM) has detected an abnormally low voltage on the ignition coil control circuit for cylinder 14, which is part of the ignition system responsible for firing the spark plug. The PCM monitors this circuit and expects to see a voltage within a specific range when the coil is commanded on or off; a low signal suggests a short to ground, an open circuit, or a faulty coil driver.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaIgnition system and misfire

Symptoms you may notice

  • Illuminated check engine light (malfunction indicator lamp) on the dashboard
  • Engine misfire, often noticeable as rough idle, hesitation, or stumbling during acceleration
  • Reduced engine power or limp mode in some vehicles
  • Shaking or vibration felt through the steering wheel or seat
  • Often no symptoms besides the warning light, especially if the misfire is intermittent

Common causes, most likely first

  1. Faulty ignition coil on cylinder 14 (internal short or open)
  2. Damaged or corroded wiring harness or connector at the ignition coil
  3. Short to ground in the ignition coil control circuit
  4. Open circuit in the ignition coil control circuit (broken wire or poor connection)
  5. Failed driver circuit inside the powertrain control module (PCM)
  6. Loose or damaged ground connection for the ignition coil
  7. Aftermarket or incorrect spark plugs causing excessive resistance and coil stress

How to diagnose and fix it

  1. Scan all modules for stored and pending codes, and record freeze-frame data to understand when the fault occurs
  2. Visually inspect the ignition coil, connector, and wiring for cylinder 14 for damage, corrosion, or loose pins
  3. Perform a resistance test on the ignition coil primary and secondary circuits, comparing to manufacturer specifications
  4. Check for continuity and short to ground on the control circuit between the PCM and the ignition coil
  5. Swap the ignition coil from cylinder 14 with a known-good coil from another cylinder to see if the misfire moves
  6. Test the PCM driver circuit with a noid light or oscilloscope to confirm proper signal output
  7. Repair or replace the faulty component (coil, wiring, connector, or PCM) and clear codes to verify the fix

Don't overlook the coil driver circuit

  • A low signal on the ignition control circuit often results from a short to ground in the wiring, which can be caused by chafed insulation against a metal bracket or engine component.
  • The code may set intermittently due to heat or vibration, so a wiggle test of the harness while monitoring live data can reveal a marginal connection that a static test misses.
  • Replacing the ignition coil without checking the control circuit can lead to repeat failures if the underlying wiring or PCM driver issue is not addressed.
  • Some vehicles use a single coil per cylinder, while others use a coil-on-plug design; the diagnostic approach is similar, but connector and pin locations vary, so always consult the specific service information.
  • A faulty spark plug with excessive gap can increase resistance and stress the coil, eventually causing a low signal code; always inspect plugs when diagnosing ignition coil codes.

Can I keep driving with P036E?

Driving with P036E is generally not recommended because a misfire can damage the catalytic converter and reduce engine performance. If the check engine light is flashing, stop driving immediately and seek repairs; otherwise, drive cautiously to a repair shop, avoiding heavy loads and high speeds.

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 all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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