VY Cranking but has no injector pulse or spark

[Ethan Miller]

Hopefully someone else has had these symptoms and can steer me in the right direction to fix it.

After turning the key to ignition I get an airbag fault and an abs fault. The car turns over but does not have an injector pulse or any spark, it does however read rpm when cranking which suggests it's not a faulty crank angle sensor (has been replaced regardless). The ecu has vats disabled as well as a mafless tune, I removed the ecu and put it in a near identical commodore with an ls1 and the same gearbox and it started without a hiccup.

It does not have a set of seats in it currently which I assume is throwing the airbag fault but I am unsure if this would disable my spark and fuel.

I also don't know what is causing the abs to fault and am unsure if this would cut spark and fuel but still allow the car to turn over.

I have checked all fuses and relays and everything lights up as it should with a test light.

Any suggestions would be greatly appreciated because I'm nearly at a dead end.

 

[Jolls]

Hopefully someone else has had these symptoms and can steer me in the right direction to fix it.

After turning the key to ignition I get an airbag fault and an abs fault. The car turns over but does not have an injector pulse or any spark, it does however read rpm when cranking which suggests it's not a faulty crank angle sensor (has been replaced regardless). The ecu has vats disabled as well as a mafless tune, I removed the ecu and put it in a near identical commodore with an ls1 and the same gearbox and it started without a hiccup.

It does not have a set of seats in it currently which I assume is throwing the airbag fault but I am unsure if this would disable my spark and fuel.

I also don't know what is causing the abs to fault and am unsure if this would cut spark and fuel but still allow the car to turn over.

I have checked all fuses and relays and everything lights up as it should with a test light.

Any suggestions would be greatly appreciated because I'm nearly at a dead end.

Hi @Ethan Miller

Firstly welcome to the forum. It is great to see a first post that clearly outlines the issue.

I'm going to make a couple of assumptions here as there is a bit of detail missing in your description.

1. It is an LS1.
2. When you changed the ECU, and it was running, the ABS and airbag faults were still there.

If the car runs with a different ECU - it sorta points me to the ECU being the issue. However, you follow a diagnostic procedure so you can, touch wood, identify the root cause and potentially have the ECU repaired.

Step 1. Go here and download a copy of the VT-VZ workshop manual. It will allow you to diagnose 90% of the issues out there by simply following the diagnostics table associated with each code. Just be aware that if there are multiple codes - triage them from the most important/most likely cause and work down from there. Resolving the one issue is likely to resolve several.

Step 2. Grab a decent scanner and read the codes, determine what is current and what is historic. The historic codes may well tell the story of what the cause of the failure is. See what patterns there are and if it points you to something in particular. Then clear the codes and try to start it. The scanner should now only show the current codes. When you have those codes you can proceed to the next step.

Step 3. Identify what codes are likely to be related to the No-Start and work your way from there. Each DTC will have a diagnostic chart for you to follow. Just be aware that some codes are thrown by a component that is not recorded in the manual. Just work from first principles, read this site to find what others have done, then work through to a solution in a systematic manner. Change one thing at at a time.

You will eventually resolve the issue.

Alternatively go to the wreckers, grab a second hand ECU and see how you go.

Cheers n Beers
Jolls

 

[Fu Manchu]

@losh1971 has an eye twitch that he is getting therapy for thanks issues like this.

 

[Ethan Miller]

Hi @Ethan Miller

Firstly welcome to the forum. It is great to see a first post that clearly outlines the issue.

I'm going to make a couple of assumptions here as there is a bit of detail missing in your description.

1. It is an LS1.
2. When you changed the ECU, and it was running, the ABS and airbag faults were still there.

If the car runs with a different ECU - it sorta points me into the ECU being the issue. However, you follow a diagnostic procedure so you can, touch wood, identify the root cause and potentially have the ECU repaired.

Step 1. Go here and download a copy of the VT-VZ workshop manual. It will allow you to diagnose 90% of the issues out there by simply following the diagnostics table associated with each code. Just be aware that if there are multiple codes - triage them from the most important/most likely cause and work down from there. Resolving the one issue is likely to resolve several.

Step 2. Grab a decent scanner and read the codes, determine what is current and what is historic. The historic codes may well tell the story of what the cause of the failure is. See what patterns there are and if it points you to something in particular. Then clear the codes and try to start it. The scanner should now only show the current codes. When you have those codes you can proceed to the next step.

Step 3. Identify what codes are likely to be related to the No-Start and work your way from there. Each DTC will have a diagnostic chart for you to follow. Just be aware that some codes are thrown by a component that is not recorded in the manual. Just work from first principles, read this site to find what others have done, then work through to a solution in a systematic manner. Change on thing at at a time.

You will eventually resolve the issue.

Alternatively go to the wreckers, grab a second hand ECU and see how you go.

Cheers n Beers
Jolls

Thanks for the repy,

Sorry, I should have worded my question better. I removed the ecu from the car that wasn't start and put that ecu into a car that is running to make sure the ecu wasn't the issue. So to the best of my knowledge it can't be the ecu that is faulting.

I use a hptuners rtd to scan and the only code that was thrown was a throttle position sensor so I have since replaced that and now have no codes on the scanner but am still getting airbag and abs faults on the dash.

Also, for context it is an ls1 in a vy maloo

 

[Jolls]

Acknowledged - got it now.

So grab the manual first and get your head into the no start diagnostics. Also get a handle on how the serial data system works and how to identify the ref voltage, earth and trigger wires so you can do some more in depth diagnosis. Most of the controlled, or controlling systems have a reference voltage, an earth and a trigger/signal wire. If the earth and ref voltages are fine then you can start chasing the triggers/signals. Chasing them requires additional tools (oscilloscope) but most issues relate to earth, ref voltage problems or broken cables so don't go splashing out on tools you don't need yet.

Given your ECM works we need to look hard at the DTCs first.

SO if you intend to resolve this one yourself grab or borrow a better scanner. There should be buckets of codes related to the airbags and the abs. Your current scanner isn't doing the job. Probably a great tuning tool - but pretty poor diagnostics one.

Go here, where there is a recent discussion regarding scan tools to get a feel for what you might consider (for a VT but the same sort of system). A tech 2 clone would be my go to for this situation; however, I think the other scanners would be Ok as well - just can't do the in depth function tests that the Tech 2 can. Perhaps one of the Victorians who has one is close and may assist for a few frothies if you are lucky.

Once you have the DTCs from the scanner follow the diagnostics trouble shooting and go from there.

You can follow the issues I had with my VY SS (Jimi) not long ago here. It took patience to get through it and several questions. We got there in the end - but it wasn't the manual that solved it - came down to a piece of wisdom that someone had tucked away in their brain box.

Post what you find and follow up and you will get plenty of support here.

Cheers n Beers
Jolls