Ford 48 Loss of ignition diagnostic module signal on the left bank or distributorless ignition coil pack fault
How to read it
Code 48 reads as 4 flashes, pause, 8 flashes on the check-engine light. Jumper the self-test input to signal return at the test connector, then run the key on engine off self test and the running self test, counting the check-engine flashes each time.
New to flash codes? The How to Read Ford EEC-IV Self-Test Codes walks through the test and what the numbers mean. The general OBD-I guide covers the rest.
What does Ford code 48 mean?
Loss of ignition diagnostic module signal on the left bank or distributorless ignition coil pack fault
Common causes of 48
- Faulty ignition coil pack
- Open or shorted ignition diagnostic wiring
- Faulty mass air flow or vane air flow sensor
- Corroded ignition connector
- PCM input fault
How to fix 48
- Confirm the code and identify the affected coil pack
- Inspect the coil pack connector and diagnostic wiring
- Test the coil pack primary and secondary circuits
- Repair wiring before replacing the coil pack
- Replace the coil pack only after the circuit test fails
Source
Source review recorded
Sources and review
Review: checked against the recorded source material.
- EEC-IV Ford trouble code table (MIL, description, type)
archived reference page (troublecodes.net via Wayback Machine)
Supports: code identity and meaning
Fetched directly. Code row matches the description used in the data file.
https://web.archive.org/web/20030720231430id_/http://www.troublecodes.net:80/Ford/eec-iv.shtml
Last updated 2026-09-25.
Report a correction for 48. Include your vehicle, the issue and a source if you have one.