I checked around, but this doesn't seem to be a common problem. My cruise control stopped working. Initially when I noticed the problem I would hit the on/off button and the cruise light would come on but the set light would flash rapidly. Now I don't even get that much. When I hit the on/off button nothing happens.

I asked the dealer about it while getting an oil change and got a canned response that I'd need to make an appt and have them look at it (with a $130 diagnosis fee).

Is there anything I can do to look in to this problem myself? I thought about checking fuses but it doesn't really sound like a fuse problem (due to the flashing set light). Has anyone else had this problem?

My cruise control is normal cruise and not the adaptive cruise. It's a 2010 G37xs. Thanks for any help!

 

Just went through this. There are a few pieces to the cruise system that all need to be working for CC to run. If any of the switches are broken, misaligned, or a wire is shorted, the system will not engage. The typical culprits are CC switches on the brake and clutch - called the "ASCD" brake/clutch switches. Additionally, the steering wheel controls should be tested to ensure they work. Apparently, the consult system can perform a test of the entire system, but it is possible to diagnose with just a multimeter.

There is a step by step process for checking each element of the cruise system in the "EC" chapter of the factory manual. Get yourself a multimeter and go through the step by step process in EC-62/428. You will need to print out the pin-outs for the connectors (also in the manual). Let me know if you need clarification on this process... it took me a while to figure it out at first. Also since this process requires the key turned to "on" while you disconnect an ECM plug - make sure you have a OBD2 scanner to reset the check engine light when you're done.

If you can rule out the electrical switches/wires/connections, the problem likely lies in the ECM (computer), or the CAN signals to the ECM (harder to diagnose/costly to repair). My results from the test are that it is an "intermittent" fault and I need to fiddle around to try and replicate the error to trace it down.

 

Thanks for the reply! It sounds like it could get a little over my head, but I do have a multimeter and I'll run through your instructions and the "EC" chapter of the manual. I appreciate the help

 

Do other steering wheel buttons work? It could be the "spindle" cable, it's the cable that does the electronics on the steering wheel and allow it to turn. I had this problem a little while back.

 

Agreed- The spiral cable would isolate a wiring/button issue since the AV and CC controls all run through these connectors (M36/M303). If the AV controls DO work, I think you'll still have to test voltage signal from the CC steering wheel buttons to see if those work or not (EC-421).

Otherwise - I found the manual to be pretty intuitive. The directions tell you which connector to test, and there are maps and circuit designs in the back of each chapter to see exactly what you are looking at. One thing to note, the connector to the ECM that the CC system is wired to is "M107". There are 3 black connectors in a line on the ECM and it is the closest one to the rear of the car (it's also the squarest shaped one).

 

No the buttons on the steering wheel to turn the cruise control on/off and set the cruise speed do not work.

Sounds like I need to RTFM a bit for some troubleshooting help

 

I've had this same problem. Works sometimes and other times it flashes. The dealer has looked at it 4-6 times over the past 2 years but have never been able to find what is causing it. It did not help that every time I would bring it to them, the flashing would stop and the cc would work fine. My problem has progressed to where (at times, not all the time) the cc will turn off if I roll the window down or press any of the ac buttons. It has recently turned itself off while set at 70 on the freeway without any input from me whatsoever. Wish I knew the problem...

 

I had same problem (intermittent flashing of the "set" light for the cruise and then eventually the cruise stop functioning altogether. I could turn it on and off but not set it). I came across this video (not my video) and it fixed my problem.