Check system error

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ajm
Posts: 1
Joined: Wed Sep 20, 2023 12:38 pm

Check system error

Post by ajm »

hi all. cross posting from another forum. normally wouldn't do that as i know it can be very frustrating and i have seen a few usernames here that i know from the other forum. so ahead of time folk, i apologise. sadly, your wrath does not come close to that of the boss whose car i seem to have cooked.

while installing a new headunit into 2014 MUX LS (whichever one has the leather seats, climate control, overhead screen, etc), i ran into problems getting a signal to or from the reverse camera. should just say that i am using an aerpro harnesses for the power/speakers and also one for the reverse camera (APVIZ01). I have earthed the video retention harness to the old bottom bracket that sat under the Clarion unit that has been removed from the car. while subsequently testing, using a test light probe, the power from the video signal (white plug) which contains the reverse trigger wire) connection to the reverse camera connection (green plug), i have managed to do something. that something remains unknown.

the result of my experimentation is CHECK SYSTEM and a big key in the display in the middle of the dash and a little red key with exclamation mark behind it on the speedo dial. when pressing the start/stop again, and i did this a few times in desperation, the dash display does come up but without displaying the selected gear (P, R, N, D, etc). in its place is a hyphen or line.

I have checked all fuses in the cabin by the steering wheel, in the box next to the battery, and also one i found in the rear quarter passenger side which i assume is for the parking sensors. I pulled a few relays also but couldn't see any scorching.

The manual says the Check System error is related to the keyless entry system but i don't know where that is controlled from exactly. RACQ looked for codes but got nothing and suggested the error will be in the Body Control Module and to get the car towed to an auto electrician.

So, has anybody else been this clever and managed to fix it? does anybody know how to reset the BCM? can someone teleport me to a distant planet where i can no longer hear my wife? actually, to somewhere i can no longer see the disdain and the "i told you so".
mydmax
Posts: 2095
Joined: Sat Oct 12, 2013 8:36 pm

Re: Check system error

Post by mydmax »

It seems fairly obvious that although you buy harnesses to complete the task of connections, are they really correct or are you simply trusting they are correct?
I would always call a voltage supply from a reverse system of the vehicle as a signal wire not as a trigger. A trigger is typical a one shot event, Bang, which may be the case, in this instance, where a signal causes an action each time it is present to complete a required function.
Did you trace and verify each wire you are connecting to, to ensure the connections of the additional looms are completing the correct paths to and from the components?

By the description you have provided of the now present fault, you seem to have connected to something, other than, a head unit related connection. Until that is found the CHECK ERROR will REMAIN.

Is the bit you earthed to, actually earthed or screwed to plastic dash frame?
Probing with a test light with a globe in it may exceed the current flow of the thing being tested and fry it internally. Any smoke? An LED with a 1K resistor may be safer of probing stuff you are not familiar with. The LED tester, make it yourself, can have a Red and Green LED facing opposite ways and so when the supply to it's probe with indicate a + or - connection and that may indicate without damage to vitals.
yatesy94
Posts: 2
Joined: Tue Mar 26, 2024 4:11 pm

Re: Check system error

Post by yatesy94 »

Hi AJM, I have a 2015 Isuzu mux LST & I am installing a new head unit & I have done the exact same thing as you this afternoon. Trying to connect the reverse signal wire for the reverse camera & the check system error has come up. I have checked all of the fuses with no luck. What ended up being the fix for your car mate?

Thanks
mydmax
Posts: 2095
Joined: Sat Oct 12, 2013 8:36 pm

Re: Check system error

Post by mydmax »

yatesy
There won't be a blown fuse UNLESS you shorted something! Is the reverse wire on the HU clearly labelled what to connect it to? ie, the reverse wire, which you can pick up FOR SURE near one of the rear lights, ie ID the reverse globe/LED feed line. The same wire will be in the wiring loom at rear LHS before it splits to go L or R. If you try and do it near the front you may connect to the wrong wire and then you might get an error appear.
I presume you know NOT TO CONNECT To any YELLOW WIRE. AIRBAGS GO BANG if you do!

Undo the battery terminal NEGATIVE and allow a time to pass and then reconnect. It should cancel the error I imagine.
yatesy94
Posts: 2
Joined: Tue Mar 26, 2024 4:11 pm

Re: Check system error

Post by yatesy94 »

Hi all, I have now found the resolution to my problem so I thought I would post the whole story here for anyone else that runs into this issue.

While installing a new headunit into my 2015 Isuzu MUX LST, I ran into problems getting a signal to or from the reverse camera. I am using the carbon car systems harness. While I was subsequently connecting the trigger wire, the power from the video signal (white plug) which contains the reverse trigger wire connection to the reverse camera connection (green plug), which I now know you don't need to do, just turn on the "reverse camera interrupt" on the headunit. I have managed to SHORT the reverse camera harness. In doing so has blown the back light 15 amp fuse. Once this happens it puts the MUX into "check system" error with a big key in the display in the middle of the dash and a little red key with exclamation mark behind it on the speedo. It also doesn't know which gear it is in, it displays dashes where the selected gear is shown (P, R, N, D). This is because in the MUX the reverse camera uses this circuit to power the camera & the Transmission inhibitor switch. So disconnecting the reverse camera from the headunit harness & replacing the 15A back light fuse resolves the issue, the 15A fuse is located below the steering wheel on the RH side pull out the little hatch. I tried attaching a photo of fuse location but it would not let me. GOODLUCK!

Cheers
Yatesy
Duck
Posts: 302
Joined: Sat Apr 29, 2017 9:58 pm
Location: Brisbane

Re: Check system error

Post by Duck »

Nice work !!!
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