Hi folks,
My 1.2 16v Punto mk2b has decided it wants the rad fan to run at all times while the engine is running. I did a quick search but couldn't find anything conclusive; one person suggested a damaged cable between the relay and the ECU but I don't *think* that's my issue (see below). Car is single speed fan and no air conditioning.
Anyone else had this?
Things I've looked at so far....
- Disconnect battery overnight
- Cleaned up all the grounds under the hood (battery to body, gearbox, body to earth block behind headlight, ECU to loom)
- Checked battery voltage
- Swapped the fan relay for a different one (no change)
- Disconnected/cleaned/visual inspection of ECU plugs & connectors under engine bay fuse/relay box
- Used a meter to check for high impedance to body/gearbox earth from fuse box (basically seeing 0 ohms)
- Used MultiECUscan to check for fault codes (none present apart from the usual side light warning in the body computer)
- Used MES to test the fan with the ignition ON but engine stopped, which responds correctly. I.e. the ECU has control of the fan, so I think on the output side of the ECU the wiring/relay/fan are probably all fine.
- Looked at the live data from OBD using MES, which says the ECU has turned the fan on (speed 1)
- Checked coolant temp and air temp sensor readings are normal
- Had a look at the air-con demand parameters in MES (the two I found said "NO" plus, the car doesn't have a/c anyway)
So far as I can tell then, the cooling fan electrics themselves are all working fine, the temperature readings are normal and there's no fault codes, yet for some reason it feels like the ECU "wants" the fan on at all times while the engine is running. Beyond engine temp, air con request, bad data from the temperature sender or a CAN issue, why else would the fan run? Am I missing something stupid?
I'm starting to think maybe the ECU has actually failed, but in my experience that's pretty rare and it's normally an external influence that gives the impression of failure. I'm a bit lost with it now. Gonna give it a week then I'm drilling a hole in the dash and putting a manual override switch in
Any help/thoughts greatly appreciated!
My 1.2 16v Punto mk2b has decided it wants the rad fan to run at all times while the engine is running. I did a quick search but couldn't find anything conclusive; one person suggested a damaged cable between the relay and the ECU but I don't *think* that's my issue (see below). Car is single speed fan and no air conditioning.
Anyone else had this?
Things I've looked at so far....
- Disconnect battery overnight
- Cleaned up all the grounds under the hood (battery to body, gearbox, body to earth block behind headlight, ECU to loom)
- Checked battery voltage
- Swapped the fan relay for a different one (no change)
- Disconnected/cleaned/visual inspection of ECU plugs & connectors under engine bay fuse/relay box
- Used a meter to check for high impedance to body/gearbox earth from fuse box (basically seeing 0 ohms)
- Used MultiECUscan to check for fault codes (none present apart from the usual side light warning in the body computer)
- Used MES to test the fan with the ignition ON but engine stopped, which responds correctly. I.e. the ECU has control of the fan, so I think on the output side of the ECU the wiring/relay/fan are probably all fine.
- Looked at the live data from OBD using MES, which says the ECU has turned the fan on (speed 1)
- Checked coolant temp and air temp sensor readings are normal
- Had a look at the air-con demand parameters in MES (the two I found said "NO" plus, the car doesn't have a/c anyway)
So far as I can tell then, the cooling fan electrics themselves are all working fine, the temperature readings are normal and there's no fault codes, yet for some reason it feels like the ECU "wants" the fan on at all times while the engine is running. Beyond engine temp, air con request, bad data from the temperature sender or a CAN issue, why else would the fan run? Am I missing something stupid?
I'm starting to think maybe the ECU has actually failed, but in my experience that's pretty rare and it's normally an external influence that gives the impression of failure. I'm a bit lost with it now. Gonna give it a week then I'm drilling a hole in the dash and putting a manual override switch in
Any help/thoughts greatly appreciated!