Invalid Engine Speed Signal
The engine control module is not receiving a valid RPM signal.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The engine's computer is supposed to get a signal about how fast the engine is running, but it's getting something wrong or nothing at all.
What the computer is actually seeing
The engine control module (ECM) looks for a specific voltage signal from the crankshaft or camshaft position sensor, typically around 0.5V to 4.5V, depending on RPM. If the signal is erratic, below 0.5V, or missing for more than 200 milliseconds, it triggers this code.
What a healthy reading looks like
Expected RPM signal voltage between 0.5V and 4.5V depending on engine speed; valid readings should fluctuate with RPM changes.
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 crankshaft position sensor wiring and connector for damage or corrosion. If damaged, repair or replace.
- 22. Check the crankshaft position sensor output voltage while cranking the engine. It should read between 0.5V and 4.5V. If outside this range, replace the sensor.
- 33. Measure the resistance of the wiring between the sensor and the ECM; expected resistance is typically below 5 ohms. If higher, repair the wiring.
- 44. Verify all ground connections of the ECM; poor ground can cause signal issues. Repair as needed.
- 55. If all else checks out, consider whether the ECM itself is faulty and test or replace as necessary.
Common causes
- Faulty crankshaft position sensor
- Wiring issues between sensor and ECM
- Failed engine control module
- Loose or corroded connectors
Typical repair cost
$$-$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's not recommended to drive for long, as it can lead to stalling and loss of engine control.
Will the code come back after clearing it?
If the underlying issue isn't fixed, yes, the code will likely return.
Why does this code show up with other codes?
Engine speed issues often correlate with overall engine performance and sensor readings, making multiple codes common.
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