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In the display next to the fuel gauge, I occasionally get "SYS" flashing. It will flash three times and then return to whatever was normally displayed (engine temp or distance to empty, etc.) It does this every 30 seconds or so. It happens only at dusk or after dark. It is fine during the day. It makes me think there is some kind of ambient light sensor somewhere in the system, but I have found nothing in the service manuals. Can someone enlighten me as what this may all be about? This is a '96 coupe.
What are the codes in Module 1? H74 H72 are the lighting code that an aftermarket radio can set that Chump mentions.
Key = OFF.
Jumper ALDL 4 to 12
Turn key to RUN.
Watch the fuel info area for the Module number. Codes are in the speedometer. When each module reaches the end of string " - - - " is displayed. Then the next module. A 1996 will have Module 1 (CCM), Module 4 (PCM) Module 9 (ABS/ASR) Module A (SIR "air bags"), and if equipped with F45 Active Suspension, Module 7.
If you get lost, turn key OFF, wait about 10 seconds, turn key to RUN and it will start over.
Report back with the codes. Include the "H" or "C".
Thank you all for your input. Yes, I had an aftermarket radio installed a while ago. I will try to figure out how to read out those codes that you are mentioning, and get that information on here.
Thank you all for your input. Yes, I had an aftermarket radio installed a while ago. I will try to figure out how to read out those codes that you are mentioning, and get that information on here.
This post should help you. But retrieve the codes first to make sure you are dealing with a code 72.
OK, have not pulled any codes. But I have discovered this -- there is a glass "eye" on the dashboard to the right of the steering wheel above the "Fuel Info," "Gauges," and other buttons. If I block that eye with my finger during the day, the SYS light will flash 3 times as described earlier. If I shine a light on it at night when it is flashing, it stops. The brightness of the speedometer display also changes when I do these things. Anybody have a clue what this is all about?
There are 4 lighting codes. H71, H72, (LCD) H73, and H74 (Green LEDs). While there isn't a code directly associated with the Ambient Light Sensor (the glass eye), my guess is that when ambient light goes down, the CCM responds by brightening the 3 lighting circuits. LCD back light, "Green" LED indicators, and the cluster incandescent dimming. When it brightens the lighting, something isn't responding the way the CCM expects it to. Watch the 3 lighting circuits I described as you shine the flashlight into the eye. Watch for a response.
In particular, pay attention to the backlighting in the power window switches, the power seat controls, the console flood light in the bottom of the rear view mirror and the 'orange' courtesy lights that are above the door handles. There is a device called "Incandescent Power Driver" that drives these bulbs. I recall a post awhile back where the guy replaced it. I think I recall that he had a SYS message associated with this device.
Here's a pic of the FSM for Ambient Light Sensor diagnostics. Sorry about the sideways.
Sys?
