P2C40 code meaning
Fan 4 Control Circuit High
Powertrain system Generic code P2Cxx codes Check engine light
What P2C40 means
P2C40 states that fan control output 4 is held at too high a level: the line has contact with battery voltage, or the driver cannot pull it down when it should. In Saab's 2011 9-5 the counterpart relay codes P0692, P0694 and P0696 stand for a relay control wire shorted to a voltage source, and the manual adds that a stage stuck on can also occur without any stored code. No manufacturer publicly documents P2C40. Typical finds are insulation worn through against a live wire, moisture bridging two pins and a defective relay or fan module input. The fan may run without pause, even after the engine is off, or not respond at all, and a fan that keeps turning can flatten the 12 V battery. Low voltage is P2C3F, the general circuit fault P2C3E.
P2C40 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2C40
- Fan 4 runs constantly, sometimes after switch-off
- Discharged 12 V battery after standing
- Check engine light
Common causes of P2C40
- Most likelyFan 4 control wire in contact with a battery-voltage circuit
- PossibleRelay or fan module input failed internally
- Less likelyMoisture bridging pins in the connector
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Cooling fan 4Fan relay 4ECM
What each part of P2C40 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| C | Area: hybrid propulsion. |
| 40 | The exact fault in that area. |
What to do next
- Note P2C40 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2C40
What does P2C40 mean?
P2C40 means "Fan 4 Control Circuit High". P2C40 states that fan control output 4 is held at too high a level: the line has contact with battery voltage, or the driver cannot pull it down when it should. It is a generic code, so it means the same on every make.
Is it safe to drive with P2C40?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P2C40 fail an emissions test?
Yes, it can. P2C40 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2C40 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P2C40 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.