Possible Gearbox / F1 Pump Issue

omar_little

omar_little

Junior Member
Messages
122
I have a potential issue with the gearbox or F1 Pump on my 2005 4200.

I drove the car the other day and all was fine, until the gearbox red warning light came on briefly and then went out again. I continued driving the car and parked it in a supermarket carpark for an hour. When I returned to the car and disarmed the alarm I could not hear the F1 pump priming and of course the car would not turn over. I tried switching the battery isolator off for a few minutes to reset the system, but that didn't work.

I decided to leave the car overnight in the carpark with the battery isolator switch in the off position. The car started without issue in the morning and I drove it home. I haven't driven it for a few days now, so not sure if the problem still remains.

Sounds like an intermittent problem. Does anyone have any suggestions? Is it worthwhile replacing the relay unit before looking at the bigger job of the F1 pump??
 
voicey

voicey

Member
Messages
660
Before you go to the trouble of buying a new relay I would test the existing one. I'd also want to know what errors the TCU logged to display the warning light.

Did you have the warning light when the car refused to turn over? The engine would normally start even with low F1 fluid pressure which makes me suspect that it could be something other than a pump/relay issue. A refusal to turn the engine over is usually because the TCU thinks that to start the engine would cause damage to the gearbox.
 
CatmanV2

CatmanV2

Member
Messages
48,859
12v across the coil, see it if switches :)

While Voicey is, as ever, the true expert, I suspect for *most* on here buying a new relay would actually be quicker and easier then trying to test one without a selection of 'stuff' ;)

Felice could do it, naturally.

When you parked, was it in gear? If it couldn't get neutral, because the pump wouldn't pressurise the gearbox, it wouldn't turn over, would it, Voicey?
C
 
omar_little

omar_little

Junior Member
Messages
122
I always turn it off in gear. When I turned it back on, it was in neutral.

CatmanV2 said:
12v across the coil, see it if switches :)

While Voicey is, as ever, the true expert, I suspect for *most* on here buying a new relay would actually be quicker and easier then trying to test one without a selection of 'stuff' ;)

Felice could do it, naturally.

When you parked, was it in gear? If it couldn't get neutral, because the pump wouldn't pressurise the gearbox, it wouldn't turn over, would it, Voicey?
C
Click to expand...
 
CatmanV2

CatmanV2

Member
Messages
48,859
Beats me then. It mist have managed to get neutral, or maybe it just thought it was in neutral.
How it would have done that without the pump priming, I'm not sure

C
 
voicey

voicey

Member
Messages
660
If you're going to replace the relay then you're going to have to remove the old one anyway. As Chris says, pull it out and apply 12V across the coil - you should be able to hear it clicking if it is working properly.

I would prefer to test the relay as the F1/CC system has a terrible habit of throwing a wobbly for no apparent reason and then working without fault for years. If you replaced the relay and it was a spurious one off problem then you'd wrongly believe that the relay was at fault (if that makes sense at all).

Also you (Chris) are correct - it wouldn't crank the engine if it was in gear and unable to select neutral.
 
conaero

conaero

Forum Owner
Messages
34,639
I had a similar issue and it turned out to be the battery connector or more so, the piggy back terminals were loose, worth checking the simple stuff first:

attachment.php
 
CatmanV2

CatmanV2

Member
Messages
48,859
voicey said:
If you're going to replace the relay then you're going to have to remove the old one anyway. As Chris says, pull it out and apply 12V across the coil - you should be able to hear it clicking if it is working properly.

I would prefer to test the relay as the F1/CC system has a terrible habit of throwing a wobbly for no apparent reason and then working without fault for years. If you replaced the relay and it was a spurious one off problem then you'd wrongly believe that the relay was at fault (if that makes sense at all).

Also you (Chris) are correct - it wouldn't crank the engine if it was in gear and unable to select neutral.
Click to expand...

That does make sense, Voicey!

C
 
CatmanV2

CatmanV2

Member
Messages
48,859
Conaero said:
I had a similar issue and it turned out to be the battery connector or more so, the piggy back terminals were loose, worth checking the simple stuff first:

attachment.php
Click to expand...

I seem to recall that issue, Matt. Was a bit of a sod to trace, no?

C
 
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