What it means
The control module detects a high signal in the EVAP leak detection pump heater control circuit. This code concerns that heater circuit, not a lambda sensor heater.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The EVAP leak detection pump heater warms the pump or related sensing components when needed. The control module monitors the heater control line and sets P240C when its signal is higher than expected, which can happen if the line is shorted to a supply voltage. This is the EVAP pump heater circuit, not a lambda-sensor heater circuit.
Common causes
Most likely first.
- Control line shorted to supply
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check engine light on
How to diagnose it
- Review freeze-frame and heater-circuit live data, if available, to confirm that the high signal occurs when the heater is commanded.
- Inspect the wiring near the pump and other power sources for pinching or insulation damage that could connect the control line to supply.
- Check heater-circuit connectors for corrosion, damaged terminals, or poor contact.
- With the circuit isolated as specified by the manufacturer, test the control line for a short to supply and check continuity.
- If the wiring is sound, test the pump-heater load and control output against the manufacturer's specification.
Common fixes
- Repair a control line pinched against a power source.
- Restore clean, secure contact at corroded or damaged connector pins.
- Replace a pump-heater element or assembly that fails the manufacturer's test.
- Repair a confirmed control-output fault in the relevant module.
Can I keep driving?
If the vehicle runs normally and there is no fuel odor or leak, short-term driving is generally possible because the code typically affects EVAP monitoring. Have the circuit checked so the emissions system can complete its checks and the check-engine light can be addressed.
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.