Ignition Signal Loss
The engine control module detects an issue with the ignition signal from the ignition coil or modules.
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What it means (plain English)
The engine is not getting the signal it needs to fire the spark plugs properly, which can lead to rough running or no start.
What the computer is actually seeing
The computer notices that the ignition timing is not changing as expected, leading to a fault condition because the ignition coil is not firing correctly during the engine cycle.
What a healthy reading looks like
Ignition signal voltage should be between 0.5 to 5.0 volts during operation; you should expect to see a stable spark pattern when testing ignition coils.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Check wiring and connectors to all ignition components for damage or corrosion. Decision: If any are damaged, repair or replace them.
- 22. Test the ignition coil(s) using a multimeter. Expected resistance values are typically between 0.5 to 1.5 ohms for primary and 5,000 to 15,000 ohms for secondary. Decision: If out of range, replace the faulty coil(s).
- 33. Check the ignition control module to ensure it is providing the correct signals. Use a scope if necessary to inspect signal consistency. Decision: If the module is faulty, replace it.
- 44. Clear the code and run the engine. If the code returns, you may have a deeper issue with the engine management system. Decision: Investigate further for ECU related issues.
Common causes
- Faulty ignition coil(s)
- Broken or damaged ignition wiring
- Bad ignition control module
- Poor connections at ignition components
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's not recommended to drive as loss of ignition can lead to engine misfires and potential damage.
Will this problem come back after I fix it?
If all faulty components are replaced and connections are secure, the issue shouldn't return.
Why is this code showing only with a misfire code?
Ignition signal loss can cause multiple ignition failures, leading to simultaneous misfire codes being triggered.
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