Ignition

P035A — Ignition Coil E Control Circuit Open

Severity: medium Drive with care, to a shop

What P035A means

The engine control module drives ignition coil E with a control signal and monitors that circuit for faults. P035A sets when the circuit looks open or the signal is outside the expected range. Coil E usually serves the fifth cylinder in firing order, but the mapping varies by engine, so confirm it in the wiring diagram for your vehicle.

Symptoms

  • Check Engine light on or flashing
  • Misfire on one cylinder
  • Rough idle
  • Hesitation or stumbling on acceleration
  • Reduced power
  • Worse fuel economy

Possible causes

  1. Failed ignition coil E
  2. Open or damaged wiring to the coil
  3. Corroded or loose coil connector
  4. Missing power or ground at the coil (fuse, relay)
  5. Faulty coil driver inside the ECM (rare)

How to diagnose

  1. Scan all codes and freeze frame data, and look for related misfire codes (P03xx).
  2. Use the wiring diagram to find which cylinder coil E serves.
  3. Inspect the coil connector and harness for corrosion, chafing, and poor contact.
  4. Swap coil E with a known good coil and see whether the code or misfire follows.
  5. Check power and ground at the coil connector with a multimeter, plus the fuse and relay.
  6. Test the control wire from the ECM to the coil for opens and shorts.
  7. If wiring and coil are good, check the control signal with a scope before suspecting the ECM.

Common fixes

  • Replace ignition coil E
  • Repair the wire or replace the damaged connector
  • Restore power or ground, replace the blown fuse or relay
  • Replace or reprogram the ECM if a driver fault is confirmed

Questions and answers

What does P035A mean?

It means the control circuit for ignition coil E is open or faulty. The ECM cannot see normal operation on that circuit, so misfires are likely.

Can I drive with P035A?

Only briefly and under light load. Ongoing misfires can damage the catalytic converter, and you should not drive if the check engine light is flashing.

Is the coil always the problem?

No. The connector, wiring, or missing power are common causes. Swapping the coil with one from another cylinder quickly shows whether the coil is at fault.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.