0850 532 0550info@otoeko.com
Cart0,00₺

Ignition C Control Signal Circuit High

Jump to the fix

Severity

High

Can I keep driving?

Avoid extended driving; visit a service soon.

First step

Read the misfire data and freeze frame first to establish which cylinders are affected and under what conditions

  • PPowertrain
  • 0Generic code
  • 3Ignition / Misfire
  • 1CSequence number

What does it mean?

On the ignition C channel the module must pull the control line low in order to trigger the coil driver. P031C is stored when the line stays high while the module is commanding it, so the current the module expects never flows. In practice this means the control path is open, has picked up resistance, or is being held up by battery voltage from another circuit. Because the neighbouring channels usually keep working normally, the shared supply and ground of the ignition assembly are rarely the problem, and the search should concentrate on this channel's own wire, its terminals and the coil input it feeds.

Symptoms

  • Continuous misfire and a rough, shaking idle
  • MIL on and flashing under load when the misfire is heavy
  • Weak acceleration and hesitation when pulling away
  • Hard starting, worse in cold or damp conditions
  • Popping from the exhaust and an unburnt fuel smell
  • Higher fuel consumption

Likely causes

  • Open or high resistance in the C channel control wire
  • Corroded, loose or backed-out terminal in the coil pack or module connector
  • Control wire shorted to battery voltage through chafed insulation
  • Open igniter input on the third channel of the coil pack or ignition module
  • Bad ground at the ignition module, so the driver cannot pull the line down
  • Faulty module output driver, considered only after the wiring has been proven good

How to fix it

  1. Read the misfire data and freeze frame first to establish which cylinders are affected and under what conditions
  2. Inspect and test the terminals in the coil and module connectors for tension and corrosion
  3. Measure the control line voltage with the ignition on and while cranking to confirm it never drops
  4. Carry out continuity and voltage drop checks from the module pin to the coil pin
  5. Test the line with the module disconnected to rule out a short to a permanently live circuit
  6. Check the ignition assembly supply and ground quality, including the fuse that feeds it
  7. Repair the wiring or renew the coil pack, then clear the code and confirm the repair on a road test

Codes From the Same System

All Fault Codes

Related Similar Codes

This information follows the generic OBD-II definition and does not replace a vehicle-specific diagnosis. The severity rating is rule-based; an authorised diagnostic reading is required for a definitive answer.