How does grounding work on an ECU engine?
During cranking, a lot of current flows through the ground strap between the engine and the battery, so there’s a voltage drop between the engine and the battery. When you have multiple ground wires that connect between the same 2 points, the current is shared between the two alternate ground paths.
Are there ground and signal wires in ECU?
This is where things can start to get confusing for some people, because in our ECU wiring harness we also have “Ground” wires. We have battery ground wires and also separate signal ground wires. It’s all too easy to look at these wires and say: “OK, ground is ground, its just a loop back to the battery” but it’s not that simple.
Can a ECU ground back to the battery?
It’s all too easy to look at these wires and say: “OK, ground is ground, its just a loop back to the battery” but it’s not that simple. While it’s very tempting and quite possible and to connect all these black wires to the chassis just about anywhere it’s definitely not advisable.
How much current is shared between ECU ground and ground strap?
Exactly how much of that current is shared depends on the relative resistances between the ECU ground and the ground strap.
During cranking, a lot of current flows through the ground strap between the engine and the battery, so there’s a voltage drop between the engine and the battery. When you have multiple ground wires that connect between the same 2 points, the current is shared between the two alternate ground paths.
This is where things can start to get confusing for some people, because in our ECU wiring harness we also have “Ground” wires. We have battery ground wires and also separate signal ground wires. It’s all too easy to look at these wires and say: “OK, ground is ground, its just a loop back to the battery” but it’s not that simple.
Why do ECUs have dedicated sensor ground wires?
This is why ECUs have dedicated sensor ground wires. If the sensor’s ground is not isolated from the body of the sensor and it has to screw onto the engine, for example many Nissan cam angle sensors, narrowband oxygen sensors and many knock sensors, then you don’t have a choice; you have to choose the star point ground at the engine.
Why do I need two ground straps on my ECU?
One of the reasons this happens a lot is because when you see ground straps on both the battery and between the block and the chassis you could be forgiven for thinking: “if one ground is good then two is better!” That, however is not the case. Let’s take a look a the problems this can cause:
Why is my ECU not working on my VW Golf?
Common failing engine ECU that causes intermittent or complete none starting of the engine. Very common ECU fault causing complete non start of the engine and diagnostic communication problems. Common failing instrument cluster for the VW Golf MK5 that causes complete or intermittent loss of display and/or incorrect reading guages.
It’s all too easy to look at these wires and say: “OK, ground is ground, its just a loop back to the battery” but it’s not that simple. While it’s very tempting and quite possible and to connect all these black wires to the chassis just about anywhere it’s definitely not advisable.