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Cooling fan on with ignition

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Old 01-20-2019, 03:42 PM
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Cooling fan on with ignition

Hi my S2 with ignition on only the cooling fan comes on and stays on. What can I check I just disconnected cooling fan control mod as I thought this might be the issue but wasn't. Temp gauge went over half when idling in 107f heat so unsure if other fan is coming on. Cheers
Code P0480 and P0481 was noted
Old 01-20-2019, 04:21 PM
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I'm pretty sure it's normal for the fan to come on if you turn on the ignition and the engine is warm. It may even do it cold, I'm not sure, but depending on what you were doing before you observed this, it may be normal.
In the normal case it will turn off after a bit of time. Like 20-30 seconds. If it doesn't, and the engine is cold, and the fan just keeps running for minutes, that's weird.

I'm not sure how P0480/P0481 are actually detected by the ECU, but one mechanism may be that it turns on the fans (or thinks it does), but the coolant temperature doesn't go down. On the 8 it may have another mechanism, like some kind of load reading on the circuit, but long story short, the ECU thinks the fan relays are not working. So while you've disconnected the mod, is it possible you need to reconnect the original wiring?

Last edited by Loki; 01-20-2019 at 04:25 PM.
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Old 01-20-2019, 04:52 PM
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I'm going to buy a new hose where sensor is tapped in. That mod isn't required on S2 apparantly.

Last edited by Sydo; 01-20-2019 at 06:48 PM.
Old 01-20-2019, 05:33 PM
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....

I took out top right relay in pic which is cooling fan 3 for s2 and it cut out. Went back on when refitted
Old 01-20-2019, 06:44 PM
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Here is how the cooling fan controls work in an S2 in tabulated form:



Originally Posted by Loki
I'm pretty sure it's normal for the fan to come on if you turn on the ignition and the engine is warm. It may even do it cold, I'm not sure, but depending on what you were doing before you observed this, it may be normal.
In the normal case it will turn off after a bit of time. Like 20-30 seconds. If it doesn't, and the engine is cold, and the fan just keeps running for minutes, that's weird.

I'm not sure how P0480/P0481 are actually detected by the ECU, but one mechanism may be that it turns on the fans (or thinks it does), but the coolant temperature doesn't go down. On the 8 it may have another mechanism, like some kind of load reading on the circuit, but long story short, the ECU thinks the fan relays are not working. So while you've disconnected the mod, is it possible you need to reconnect the original wiring?
Per service manual, this is how the P0480 and P0481 work:



Naturally, it covers how to repair the codes. It's mostly checking open circuits, shorts, poor connections, etc. ASH8 has the service manuals posted up in this forum.
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Old 01-20-2019, 07:16 PM
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Thanks Jinx so according to that my fan shouldn't be on at start up ?
Old 01-20-2019, 07:36 PM
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Definitely not on a cold start unless you have your A/C on. Hot starts will depend on the ECT, as the table indicates.
Old 01-20-2019, 07:47 PM
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Aircon off. I have swapped around relays and the same. The fan that is operating when cold is number 3 in fuse box
Old 01-20-2019, 11:29 PM
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https://www.rx8club.com/series-ii-te...manual-247192/

Download the workshop manual and start following their procedures for troubleshooting. I would think there is a short somewhere in the circuit.
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Old 01-22-2019, 01:59 AM
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Is your coolant temp sensor OK?
Old 01-22-2019, 02:16 AM
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Originally Posted by dannobre
Is your coolant temp sensor OK?
Not sure mate going over it now. How can we check ?
Old 01-22-2019, 02:48 AM
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Temp is reading on scanner ok
Old 01-22-2019, 09:19 AM
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I've heard of people wiring up a manual switch somewhere in reach of the driver. Any chance the PO did this?
Old 01-22-2019, 11:40 AM
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Originally Posted by NotAPreppie
I've heard of people wiring up a manual switch somewhere in reach of the driver. Any chance the PO did this?
That would be the fans on low mod. I did it. Works great when the AC is off. If this was done, there would be an extra wire running from the switch to the relay box, and another wire running from the switch to ground.
Old 01-22-2019, 02:16 PM
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Had a look no switch. I wonder if this problem interferes with other fan speeds ?
Old 01-23-2019, 09:36 AM
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Who knows? You get those electrical pixies dancing in a circle and all bets are off.
Old 01-24-2019, 03:29 PM
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Bought a new coolant temp sensor will try that
Old 01-24-2019, 03:37 PM
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Originally Posted by UnknownJinX
Here is how the cooling fan controls work in an S2 in tabulated form:





Per service manual, this is how the P0480 and P0481 work:



Naturally, it covers how to repair the codes. It's mostly checking open circuits, shorts, poor connections, etc. ASH8 has the service manuals posted up in this forum.
Would you know where cooling fan relay 4 and 5 are ?
Old 08-08-2020, 04:25 PM
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We're you able to correct the issue? I think I have the same issue.
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