Engine Position Sensor Circuit High Voltage
This code indicates a high voltage issue in the engine position sensor circuit.
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)
Inside the engine control module (ECM), the engine position sensor sends voltage signals that tell the ECM where the engine's crankshaft or camshaft is positioned. If the voltage from this sensor goes above 5 volts for too long, the ECM flags a problem.
What the computer is actually seeing
The ECM monitors the voltage from the engine position sensor. Normal voltage readings should be between 0.5 to 4.5 volts. If it sees a voltage over 5 volts, it sets SPN 3700.
What a healthy reading looks like
Expected voltage from the engine position sensor should be between 0.5V - 4.5V under normal operating conditions.
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.
- 1Check the engine position sensor wiring for damage, frays, or corrosion. Visually inspect and ensure all connections are tight.
- 2Using a multimeter, measure the voltage at the engine position sensor connector while the engine is running. Expect readings between 0.5V and 4.5V. If over 5V, proceed to the next step.
- 3Disconnect the engine position sensor and check the voltage at the harness connector leading to it with the ignition on. If still above 5V, check wiring to the ECM for shorts to power.
- 4If voltage is normal with the sensor disconnected, replace the engine position sensor. If the issue persists, suspect the ECM.
Common causes
- Shorted wiring or connector issues in the sensor circuit
- Faulty engine position sensor
- ECM malfunction causing incorrect readings
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It’s not recommended as high voltage can lead to other system failures; address soon.
Will this code come back after clearing?
If the underlying issue isn’t fixed, yes, it will return.
Why does this code sometimes pair with SPN 3400?
SPN 3400 indicates another sensor issue that often coincides with position sensor problems.
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