What it means
Same as P23C3 with the signal voltage above the plausible range. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
At a glance
- Usually lights the check-engine light
How it works
The position sensor on coolant bypass valve C reports the valve's position to the control module. This code sets when the signal rises above the plausible range, which can happen if the signal wire is shorted to a supply voltage or the connector has a fault.
Common causes
Most likely first.
- Signal shorted to supply
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check engine light
- Possible abnormal engine temperature or weak cabin heat
How to diagnose it
- Check freeze-frame data and live valve C position readings to see whether the high signal is constant or intermittent.
- Inspect the valve C connector and harness for pinched or heat-damaged wiring, corrosion, water entry, and pushed-back pins.
- Move the valve C harness carefully while monitoring the position signal to see whether it drops or changes when the wiring is disturbed.
- Measure the position signal, supply, and ground against the manufacturer's specification to verify the high reading at the sensor.
- With power isolated as specified by the manufacturer, test the signal wire for a short to supply and check connector pin contact.
- If the wiring and connector pass, test the valve C position sensor and its actuator circuit for an internal fault.
Common fixes
- Repair signal wiring that is pinched or shorted to a supply wire.
- Restore proper contact or replace damaged terminals at the valve C connector.
- Repair damaged harness insulation where it is contacting a power source.
- Replace the valve C position sensor if its output remains high with sound wiring and connector contact.
Can I keep driving?
If engine temperature is stable, a short cautious drive is generally possible, but watch the temperature gauge and stop if it becomes abnormal. The high position signal may disrupt coolant routing, causing overheating or poor cabin heat.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.