RangeRovers.net Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
I’m a new P38 owner trying to clear up my last problem in order to pass my emissions test. I have a 2001 Rover with the 4.6 HSE motor. The SES light is on, with only one code present, 1669. I have already removed the ECM fan, verified it is operating with 12 VDC applied, cleaned it and even tried installing a spare fan. The code and light returned. I checked for 12 VDC coming from the ECM and found I am only getting 7.8 VDC. I’ve searched the forums and looked at some wiring diagrams but I’m wondering if anyone knows what supplies the voltage for the ECM fan? Is it a relay? Is it driven by a thermostat somewhere?
 

·
SUPER MODERATOR
Joined
·
27,705 Posts
When you post an error code, please post what you believe the code is for so folks don;t have to go look it up.
 

·
Registered
Joined
·
1,295 Posts
From the schematic it appears that the ground is switched in the ECM whilst power is fed from F26. Not a complete answer to your question, but you should see full vBatt at pin 3 of C0646 (unplugged) with ignition in P2. If you don't see vBatt, check connections and splices back to F26.
Fan should then run if pin 1 is grounded.
eboxfan.JPG
 

·
SUPER MODERATOR
Joined
·
27,705 Posts
The ebox fan is fed from fuse 26 through connector C0646 on pin 3 at the fan. details are in the ETM in RAVE. Yes, if the fan fails it will trigger the CEL... amber because of the ECU over heats and fails you will be instantly stranded.
 

·
Registered
Joined
·
1,295 Posts
This extract shows the trigger parameters for the ECM fan
eboxfan2.JPG
 

·
SUPER MODERATOR
Joined
·
27,705 Posts
yea what Bean posted while I was typing... dang I miss the old crossposting warnings... :lol:
 

·
Registered
Joined
·
4 Posts
Discussion Starter #7
I appreciate all of the quick and quality responses. I’ve determined the voltage drop was caused by a poor ground. It appears as though the ECM provides the ground, and bypassing it to ensure a proper ground allows the fan to operate normally. However it seems as if the logic for the circuit comes from the ECM (I’m assuming the internal thermostat. Looks like I’m headed back to the parts yard to buy an ECM, and pray it doesn’t have it’s own issues.
 

·
Registered
Joined
·
1,295 Posts
Change the ECM and you'll have to resynch the BECM/ ECM amd reset the adaptive values. Will need dedicated diagnostics plugging in to do that.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #9
As a last ditch effort I decided to open the ECM and clean the board, there were spots of corrosion but I’ve seen worse. After installing it with no change to the problem, I’m now waiting for a call back from the dealership. Hopefully one of the techs has some experience with this issue.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #10
Update: so after taking it to the dealer for the ECM replacement it turns out I made a rookie mistake. I tested the ECM fan with direct power and it worked, however I failed to check the resistance across the fan motor(which was 6 megaohm). So turns out a new fan will be my fix. Hopefully this won’t fool someone else in the future.
 
1 - 10 of 10 Posts
Top