2003 CDT fuel pump malfunction

chambl01 · 22nd February 2022, 19:37

Hi all,

No power to diesel fuel pumps. Fuel relay tested and working, pump fuse looks good, pumps tested and working too. With no power to pumps, would it be an ECU issue as can't see anything likely to prevent power getting to them. There's clearly an issue somewhere but not sure where. Car was was working fine and one day just wouldn't start. When power bypassed to battery pumps work. Would a T4 show where the failure is and if linked to the ECU, is it repairable. Trying to keep costs down and don't want to write the car off just yet. I'll probably have to get it transported as no T4 local to me. ☹️

Any further suggestions appreciated.
Thank you.

trikey · 22nd February 2022, 19:55

If it has been wet, the fuel pump drivers on the ecu will have bitten the dust.

Do you have the oil light illuminating when the ign is switched on?

chambl01 · 23rd February 2022, 03:40

Quote:

Originally Posted by trikey

If it has been wet, the fuel pump drivers on the ecu will have bitten the dust.

Do you have the oil light illuminating when the ign is switched on?

Yes, oil light comes on .

dave lincs · 23rd February 2022, 06:55

Most likely it will be the ECU as Trikey has said but might be worth checking the plugs under the engine compartment fusebox

Mike Noc · 23rd February 2022, 12:59

Worth checking the wire from the control side of the relay back to the ECM plug. These have been known to break. Black /purple if I remember correctly.
With the key to position II there is power to the control side and the ECM switches the return.

chambl01 · 23rd February 2022, 14:02

Quote:

Originally Posted by Mike Noc

Worth checking the wire from the control side of the relay back to the ECM plug. These have been known to break. Black /purple if I remember correctly.
With the key to position II there is power to the control side and the ECM switches the return.

No harm checking it out. 👍

chambl01 · 25th June 2022, 11:35

Quote:

Originally Posted by chambl01

Hi all,

No power to diesel fuel pumps. Fuel relay tested and working, pump fuse looks good, pumps tested and working too. With no power to pumps, would it be an ECU issue as can't see anything likely to prevent power getting to them. There's clearly an issue somewhere but not sure where. Car was was working fine and one day just wouldn't start. When power bypassed to battery pumps work. Would a T4 show where the failure is and if linked to the ECU, is it repairable. Trying to keep costs down and don't want to write the car off just yet. I'll probably have to get it transported as no T4 local to me. ☹️

Any further suggestions appreciated.
Thank you.

UPDATE to my original post. T4 test concluded the pumps and injectors wernt communicating with the ECU and highly likely the problem. The ECU was sent off to JULES and identified the problem. New virgin ECU delivered and cars working like a dream.

I was weighing up the cost of a new second hand car but repair was definately the best option and delighted to be driving the 75 again. Flew the MOT with only i minor advisory. Very impressed

22nd February 2022, 19:37	#1
chambl01 Avid contributor Rover 75 Join Date: Aug 2014 Location: Cardiff Posts: 162 Thanks: 151 Thanked 75 Times in 28 Posts	2003 CDT fuel pump malfunction Hi all, No power to diesel fuel pumps. Fuel relay tested and working, pump fuse looks good, pumps tested and working too. With no power to pumps, would it be an ECU issue as can't see anything likely to prevent power getting to them. There's clearly an issue somewhere but not sure where. Car was was working fine and one day just wouldn't start. When power bypassed to battery pumps work. Would a T4 show where the failure is and if linked to the ECU, is it repairable. Trying to keep costs down and don't want to write the car off just yet. I'll probably have to get it transported as no T4 local to me. ☹️ Any further suggestions appreciated. Thank you.

22nd February 2022, 19:55	#2
trikey Premium Trader Rover 75 Join Date: Nov 2010 Location: Devon Posts: 33,764 Thanks: 8,837 Thanked 14,831 Times in 8,030 Posts	If it has been wet, the fuel pump drivers on the ecu will have bitten the dust. Do you have the oil light illuminating when the ign is switched on? __________________ Lest we forget..

23rd February 2022, 06:55	#4
dave lincs Posted a thing or two Rover 75 Saloon Join Date: Mar 2014 Location: Louth Posts: 1,409 Thanks: 380 Thanked 986 Times in 476 Posts	Most likely it will be the ECU as Trikey has said but might be worth checking the plugs under the engine compartment fusebox

23rd February 2022, 12:59	#5
Mike Noc This is my second home Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4. Join Date: Jul 2009 Location: Hampshire Posts: 11,547 Thanks: 3,470 Thanked 3,119 Times in 2,247 Posts	Worth checking the wire from the control side of the relay back to the ECM plug. These have been known to break. Black /purple if I remember correctly. With the key to position II there is power to the control side and the ECM switches the return.