Emissions Control Sys - Data Validity
Emissions control system data is outside of expected range.
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What it means (plain English)
The emissions control computer is getting unexpected data, likely from a sensor that's reading incorrectly.
What the computer is actually seeing
The ECM is monitoring the emissions system sensors and finds that the values do not match what it's programmed to expect, leading to a potential emissions problem.
What a healthy reading looks like
Typical values for sensor voltage should be between 0.5V to 4.5V depending on the specific sensor type and condition.
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. Inspect the wiring and connectors for the emissions control system sensors. Look for signs of damage or corrosion.
- 22. Check the fluid levels relevant to emissions systems (e.g., DEF level for SCR systems).
- 33. Use a scan tool to read live data from emissions sensors. Ensure that voltage signals are within expected ranges.
- 44. Compare sensor readings against manufacturer specifications in a service manual or database.
- 55. If readings are still incorrect, replace the faulty sensor and retest the system.
Common causes
- Faulty sensor
- Corroded or damaged wiring
- Poor electrical connections
- Exhaust leaks affecting sensor readings
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's better to fix this soon as it affects emissions; however, you can drive it short distances if necessary.
Will this code come back after clearing?
If the fault is not resolved, the code will likely return after a few drive cycles.
Why does this code appear with SPN 606?
Both codes relate to the emissions control system and often signify issues tied to the same fault.
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