[Sparky_]

Hey guys

I've swapped in a new engine harness and now I'm getting a fuel pump relay error code 69 in ms4x flasher and INPA

The wiring all tests out good and so does the relay.

Any suggestions where to look next?

 

[Sapote]

The wiring all tests out good and so does the relay.

is the pump running?

 

[Sparky_]

is the pump running?

Yes, kind of sounds like it cuts out when I push the gas

 

[markusmarkus]

Why did you swap in a new harness? Did you do an engine swap or was the old harness bad? Are you sure the new harness is compatible with your car?

 

[Sparky_]

Why did you swap in a new harness? Did you do an engine swap or was the old harness bad? Are you sure the new harness is compatible with your car?

Old harness was destroyed by previous owner.

The new harness was ms42, so I changed the pins to i suit ms43. I did not touch the fuel pump relay wiring. Could it be something in the ecu?

 

[BaliDawg]

Username checks out.

 

[Sparky_]

Username checks out.

Correct! Embarrassing part is, I am an apprentice electrician 🤦‍♂️

 

[Sapote]

I am an apprentice electrician

Yes, kind of sounds like it cuts out when I push the gas

OK, so when the fuel cuts out, I would check if the relay output is 12v or not, and if not, then is the relay energized by the DME, and if not then check at the DME connector if the pin that connected to the relay has 12V (or grounded if it is active low) to energize the relay.

 

[Sparky_]

Y

OK, so when the fuel cuts out, I would check if the relay output is 12v or not, and if not, then is the relay energized by the DME, and if not then check at the DME connector if the pin that connected to the relay has 12V (or grounded if it is active low) to energize the relay.

Thought of that earlier, hooked up my meter to the pump. While revving etc pump still holds around 12.6v, seems fine?

 

[Sapote]

While revving etc pump still holds around 12.6v, seems fine?

normal.

 

[Sparky_]

normal.

Any idea why I've got a fuel pump relay fault then?

 

[markusmarkus]

The relay could be going bad. Maybe the DME is checking pump voltage and is seeing something that you can’t see with a meter. My advice is to buy a new relay. It’s cheap insurance.

 

[Sparky_]

The relay could be going bad. Maybe the DME is checking pump voltage and is seeing something that you can’t see with a meter. My advice is to buy a new relay. It’s cheap insurance.

I've replaced it with a whole bunch of spare ones that I have. Seems odd

 

[Sapote]

Any idea why I've got a fuel pump relay fault then?

If the pump got 12v then the relay is energized for sure, or maybe it is energized all the time and causing the error code? Are you sure the pump only run for about 2sec when turn the key to ON?

 

[NZ00Z3]

Have you checked the wiring diagrams to see what is different between the MS42 and MS43 harnesses?

Get your wiring diagrams here. BMW WDS Online

 

[Sparky_]

If the pump got 12v then the relay is energized for sure, or maybe it is energized all the time and causing the error code? Are you sure the pump only run for about 2sec when turn the key to ON?

Yep, in second position pump primes then switches off, sounds okay

 

[Sparky_]

Have you checked the wiring diagrams to see what is different between the MS42 and MS43 harnesses?

Get your wiring diagrams here. BMW WDS Online

Yes done that, everything seems identical

 

[MrMCar]

Any idea why I've got a fuel pump relay fault then? View attachment 922114

DTC = traction control system. Usually DTC fault # 69 is a pressure problem.
Where did you get a fuel pump relay related to this?
Care to share an entire screen shot?

 

[Sparky_]

DTC = traction control system. Usually DTC fault # 69 is a pressure problem.
Where did you get a fuel pump relay related to this?
Care to share an entire screen shot?

I'll send you screenshots later tonight

 

[Sparky_]

DTC = traction control system. Usually DTC fault # 69 is a pressure problem.
Where did you get a fuel pump relay related to this?
Care to share an entire screen shot?

Here you go, this issue doesn't seem to affect the running of the car now. Just wondering why it's there