RSV1000R 2004 Starting Issue – No Ground to Star

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   Hi everyone,
I’m having some trouble with my 2004 Aprilia RSV1000R and could really use some advice.

The issue: when I press the start button, nothing happens.
The engine starts and idles (although it idles quite high) when bridging the starter relay directly, but the starter relay doesn’t engage when using the start button.
After some investigation, it appears that the bike is not switching the ground for the starter relay. The 12V supply is present, but it’s not being pulled to ground when the button is pressed.
Here’s what I’ve done so far:

Tested and verified the immobilizer (although I’m not 100% sure if it could still be causing issues)

Replaced the starter relay with a proper Hitachi unit

Replaced the battery (new and fully charged)

Replaced the start/stop switch

Checked, cleaned, and secured all connectors

Inspected and tested the ground points (negative terminals/mass connections)

Swapped and tested all relevant relays

Result:

None of these actions have resolved the problem. The bike still won’t start through the normal circuit.
Symptoms:

Starter relay gets 12V but doesn’t ground

Engine starts immediately when bridging the relay manually

Engine idles quite high once started

No click or sign of engagement when pressing the start button
Has anyone encountered a similar issue?

Could the immobilizer still be interfering somehow?

Or could it be something deeper in the wiring harness, ECU, or a hidden ground fault?
Any ideas, tips, or experiences would be greatly appreciated!
Thanks a lot,
Mike

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Mikado1994 Members Profile Send Private Message Find Members Posts Add to Buddy List L Plates Joined: 28 Apr 2025 Location: Ede Status: Offline Points: 3	Post Options Post Reply Quote Mikado1994 Report Post Thanks(0) Quote Reply Topic: RSV1000R 2004 Starting Issue – No Ground to Star Posted: 28 Apr 2025 at 09:08
	Hi everyone, I’m having some trouble with my 2004 Aprilia RSV1000R and could really use some advice. The issue: when I press the start button, nothing happens. The engine starts and idles (although it idles quite high) when bridging the starter relay directly, but the starter relay doesn’t engage when using the start button. After some investigation, it appears that the bike is not switching the ground for the starter relay. The 12V supply is present, but it’s not being pulled to ground when the button is pressed. Here’s what I’ve done so far: Tested and verified the immobilizer (although I’m not 100% sure if it could still be causing issues) Replaced the starter relay with a proper Hitachi unit Replaced the battery (new and fully charged) Replaced the start/stop switch Checked, cleaned, and secured all connectors Inspected and tested the ground points (negative terminals/mass connections) Swapped and tested all relevant relays Result: None of these actions have resolved the problem. The bike still won’t start through the normal circuit. Symptoms: Starter relay gets 12V but doesn’t ground Engine starts immediately when bridging the relay manually Engine idles quite high once started No click or sign of engagement when pressing the start button Has anyone encountered a similar issue? Could the immobilizer still be interfering somehow? Or could it be something deeper in the wiring harness, ECU, or a hidden ground fault? Any ideas, tips, or experiences would be greatly appreciated! Thanks a lot, Mike

Spoonz Members Profile Send Private Message Find Members Posts Add to Buddy List Admins Group Joined: 11 Feb 2008 Location: North Devon Status: Offline Points: 10957	Post Options Post Reply Quote Spoonz Report Post Thanks(0) Quote Reply Posted: 28 Apr 2025 at 12:07
	The high idle is often a sign of an immobilisor fault and also Its function when active is to interfere with the start circuit. But the intermediary is the ecu itself so that’s a possibility although never heard of one doing that. Does the immobilisor light function as you would expect when active/inactive. One other thing to do is introducing a ground via a separate lead to various points in the loom ( via connector blocks ) to confirm if the fault is pre/post ecu for example . Even though you might have a functioning start switch, is the signal going anywhere outside of the right switchgear ? You could have a broken wire etc.

Mikado1994 Members Profile Send Private Message Find Members Posts Add to Buddy List L Plates Joined: 28 Apr 2025 Location: Ede Status: Offline Points: 3	Post Options Post Reply Quote Mikado1994 Report Post Thanks(0) Quote Reply Posted: 30 Apr 2025 at 07:44
	Thanks for the suggestions. I’ve measured all the wires in the relevant areas, including both switchgear and loom branches to and from the ECU – no broken wires or cable issues found. I also confirmed that the start/stop switch is indeed sending a signal or ground to the ECU, but that’s where it seems to stop – no further response from there. So the switch appears to be doing its job, but nothing happens past the ECU input. Would it be possible for you to send me a bypass module (or matching bypass) for the immobiliser, just to rule it out? Alternatively, I’m also able to open up the immobiliser unit and resolder the internal connections if you think that might be worth a try.

Spoonz Members Profile Send Private Message Find Members Posts Add to Buddy List Admins Group Joined: 11 Feb 2008 Location: North Devon Status: Offline Points: 10957	Post Options Post Reply Quote Spoonz Report Post Thanks(0) Quote Reply Posted: 30 Apr 2025 at 11:11
	I’m aware that you have tried a bypass suggested by another forum. Did that consist of linking wires together ? Just so I know as that method is incomplete. Don’t say what you did publicly though. Soldering the connections might help. It depends on why the immobilisor failed internally. Some have burnt out boards.