What it means
Same as P23C3 with the signal voltage below 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 sends a signal showing the valve's position to the control module. This code sets when that signal is lower than the plausible range, commonly because it is shorted to ground or its connection has excessive resistance.
Common causes
Most likely first.
- Signal shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- Check engine light
- Possible abnormal engine temperature or weak cabin heat
How to diagnose it
- Review freeze-frame data and live valve C position data to determine whether the low signal is current or intermittent.
- Inspect the valve C connector and nearby harness for water intrusion, corrosion, chafing, or pins pushed back in the connector.
- With the code active, carefully move the valve C harness while watching the position signal to check for a change that points to an intermittent short or poor contact.
- Measure the valve C position signal and sensor supply and ground against the manufacturer's specification to confirm which circuit is low.
- With power isolated as specified by the manufacturer, check the signal wire for a short to ground and inspect connector pin fit.
- If the wiring is sound but the signal remains low, test or replace the valve C position sensor according to the manufacturer's procedure.
Common fixes
- Repair chafed signal wiring that is shorted to ground.
- Clean or replace corroded valve C connector terminals and restore proper pin fit.
- Repair a damaged sensor ground or supply connection if testing identifies it.
- Replace the valve C position sensor if wiring checks pass and its output remains below specification.
Can I keep driving?
A short drive may be possible if engine temperature stays normal, but monitor the temperature gauge closely and stop if it rises abnormally. The low position signal can prevent proper coolant routing and lead to overheating or weak 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.