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Any idea what might be the problem with dashboard warning lights randomly going on? Today I discovered a way to make the light appear by pressing the gas lid open button twice:
Sometimes the lights go on randomly. Another symptom is that when the key is removed, the radio and climate control panel lights stay on until the battery is drained. What could be the problem? The dimmer switch which is a common problem is turned off.
First thing will the car start when you see this ???...looks like a serial data bus issue but never seen it happen when unlocking the fuel door...what happens is that one of the cars modules...PCM, BCM, IPC etc. loses a power or ground and that power or ground back feeds onto that data line...if you watch in your video you can see the fuel tank go to 'E" and the water temp gauge max out and the DIC warning messages...without touching anything if you have a voltmeter when all this is happening take your voltmeter and see what you have on pin 2 of the DLC...with the key ON if the data bus is OK you will see the voltage jump around between 0.2 to maybe 0.4 volts...if you see 12 volts the data bus is shorted to power and if you see 0 volts it may be shorted to ground...with an ohmmeter connected between pin 2 and a clean ground you should see more than 350 ohms with battery disconnected...way more...if you have a scan tool see if you can communicate with the car...if shorted to power or ground you will not be able to communicate...I've actually jumped from pin 16 (12 volts) to pin 2 and seen all the things you are seeing...those modules must have some type of current limiting resistors in them that will prevent damage to the modules.
First thing will the car start when you see this ???...looks like a serial data bus issue but never seen it happen when unlocking the fuel door...what happens is that one of the cars modules...PCM, BCM, IPC etc. loses a power or ground and that power or ground back feeds onto that data line...if you watch in your video you can see the fuel tank go to 'E" and the water temp gauge max out and the DIC warning messages...without touching anything if you have a voltmeter when all this is happening take your voltmeter and see what you have on pin 2 of the DLC...with the key ON if the data bus is OK you will see the voltage jump around between 0.2 to maybe 0.4 volts...if you see 12 volts the data bus is shorted to power and if you see 0 volts it may be shorted to ground...with an ohmmeter connected between pin 2 and a clean ground you should see more than 350 ohms with battery disconnected...way more...if you have a scan tool see if you can communicate with the car...if shorted to power or ground you will not be able to communicate...I've actually jumped from pin 16 (12 volts) to pin 2 and seen all the things you are seeing...those modules must have some type of current limiting resistors in them that will prevent damage to the modules.
Thanks for a quick reply! Yes, the car shuts down and starts normally when the error lights come on. After starting the car everything is normal for a while. It might take a few minutes before the lights come on randomly and it might be a random event when the errors appear after opening the gas lid (I just happened to make it happen 3 times in a row and that's how I know when to start recording the video).
I do have a voltmeter and I'll take a look based on your guide. I already cleaned the grounding points under the hood and in the driver's footwell area (close to where the hood is opened) with no impact. Any tips on other grounding points which might cause the problem?
If you don’t have a scan tool you can use the cars built in “code reader”…see what codes are stored and most likely you’ll see “U” or communication codes…unless you know what’s causing the issue there is no need to clean the grounds under the hood…below are the items that use those 2 ground points…there are some things we can try but it’s better to see if there is actually a data bus problem first.
without touching anything if you have a voltmeter when all this is happening take your voltmeter and see what you have on pin 2 of the DLC...with the key ON if the data bus is OK you will see the voltage jump around between 0.2 to maybe 0.4 volts...if you see 12 volts the data bus is shorted to power and if you see 0 volts it may be shorted to ground...with an ohmmeter connected between pin 2 and a clean ground you should see more than 350 ohms with battery disconnected
Here's what the voltmeter says with your instructions:
1.2 volts doesn’t look good if you are on pin 2 on the DLC with key ON…if you can remove the combs from both splice packs check the voltage readings on each wire with the key ON.
I have a 2002 and had that same problem problem. It also used to effect my auto climate control too, the fan motor would not work and the ac display would go blank, and the reduced speed error. I replaced the ignition key switch. There is too much current on a pin that melts it. Look up C5 Ignition Switch Repair Bill Curlee does a great job in the thread, good luck
Warning lights on dash
