OBD
P03FF
Ignition L Control Signal Circuit High
What it means
P03FF means Ignition L Control Signal Circuit High.
Check these first
- A short to voltage on the ignition L control wire
- A failed ignition coil on the L circuit
- A chafed L harness touching a power wire
- A bad coil ground
- An ECM driver fault on the L channel
What to do next
- Inspect the L circuit wire for a short to voltage
- Test the L coil for an internal short
- Check the L harness routing near power wires
- Verify the coil ground is clean and tight
- Replace the coil or repair the L wire
- Clear the code and retest
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Updated
Generic SAE J2012 definition. Last updated 2026-10-10.