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peterpete190, Auto Technician
Category: Infiniti
Satisfied Customers: 27853
Experience:  Auto repair Technician with 17 years experience.Past ASE and other certifications.
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Infiniti G35: Ryan,2003 G35 Sedan. I have been having

Customer Question

Hi Ryan,
2003 G35 Sedan.
I have been having more or less the same issue for about 3 years now. ABS / SLIP / VDC lights !!! (C1142 pressure sensor circuit ) It first started by getting the lights while driving, but after restarting the car they would disappear. The eventually came on more often. Eventually one day they started coming up as soon as I started the car. (they stay off as long as I hold the brake while starting the car, the light come up when as soon as I release the brake).
I was driving with the lights on every day for about 5 months before having the time to look at it.
After troubleshooting everything I could, all the sensor etc, unplugging all connectors, etc nothing helped. Took the car apart a couple of times and put everything back together but nothing helped. Light come on right after starting the car. I checked and actually changed the brake switch, it did not help. Also your rear brakes lights and/or reverse could be triggering the lights, but I am not having a problem with them.
One day out of the anger I started the car and slammed the brakes really really hard about 10-15 times and the lights did not come on.
I turned the car off and on again, no lights. Drive the car for a few days still nothing. I guess it fixed itself from me slamming the brakes. Drove like this with no lights for about a year.
The lights are back again, no issues for a year. starting the car now gives me the lights again. I have scan tool (autoenginuity) which makes looking for issues a little easier. I check all abs / speed sensor etc. All is good. Only code is the C1142 pressure sensor circuit.
Finally today I pulled out the service manual and started checking everything based on the manual. check ground between connectors and VDC/ABS control unit. I did not finish going through the whole process yet, but everything I checked seem to have indicated that everything is just fine.
Got tired and stopped for today, put everything back together. Light is still on. The only thing that I did not do during the last 3 years is actually replace the ABS actuator/pump. They are cheap enough on ebay to try but you changed yours and it did not help.
Don't really feel like to going through changing it if that is not the problem.
I am stuck on ideas what the problem really is, however, I don't think it is actually the pump. It work for over a year after the first time I had the issue.
I finally had infinti dealer troubelshoot it and they said they need to replace the ABS actuator (I didn't think that was the problem) They replaced it at my cost of $1400. The car still doesn't work. I will not take it back to the dealer anymore.
The only thing that I can add is the it started happening during the winter. Also the second time around when the lights come on after a year of being clear, it was winter again and while driving over a speed bump is when the lights come on again. 6 months later and the lights are still on, every time I start the car.
I can also say that if and when I try to brake harder, I do hear something clicking/pulsating like a relay or something like that. (Like the pump or something sending pulsed to the brakes. not sure if that is it.
Submitted: 1 year ago.
Category: Infiniti
Customer: replied 1 year ago.
I did check the obvious items, like rotors, pads, brake fluid, etc.Also, I don't need to start the car to get the lights, just turn the ignition to ON. but the lights do not come up as long as I press and hold the brake pedal.thought maybe one of the speed sensor was off, drove the car around and monitor all speed sensors with autoenginuity, after the excel log files for the last 20minutes, all sensors showed the same speed every single best conclusion is that I have a bad ground somewhere. I did check the brake lights, etc.
Expert:  peterpete190 replied 1 year ago.
My name is ***** ***** I am a professional here at Just Answer. I noticed that your question was not getting a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.
YOur lights should come on with the key on before the start position as a indicator test.If the lights do not come on with the key on if you have your foot on the brake pedal from here this sounds like the anti lock brake control unit/ecu itself is at fault as it controls these lights.I have seen temperatures affect the operation of the anti lock brake control unit and had to replace the unit for this fault here.I suspect this may be the cause here.I would finish the diagnostics you started to see what it points to.
Thanks Pete
Customer: replied 1 year ago.
I did finish my diagnostics based on the service manual and it says the ABS actuator is bad and needs to be replaced. I don't really agree with this, as Infiniti came to the same conclusion and replaced it, it of course did not fix the problem. I never thought the ABS actuator is was bad, if it were bad, it would not have been working for over a year before starting to give me the lights again. And the fact that the last time the lights come on when I was driving over a speed bump pretty fast. I really don't think the ABS actuator decided to brake because of a speed bump.
Expert:  peterpete190 replied 1 year ago.
If the abs control unit/ecu is at fault it can lead to false testing which can lead to the actuator.With the light issue here that you described this sounds like the anti lock brake ecu is the cause and is most common.I have seen the hydraulic unit fail as well but with what you have here this sounds more like the abs ecu at fault.
Thanks Pete
Customer: replied 1 year ago.
I guess it could be the VDC/ABS ECU, but to summarize some key points. System works find, one day I get the three lights, but lights go away after I restart the car. a couple of days some scenario lights turn off after a restart. This start to happen more frequently. One day the lights come on and stay on. It's like this for at least 6 months, because I really have to the time to look at it. checked everything and could not find the reason why the lights are there. Out of frustration slammed my foot on the brake at least 10-15 times. the next time I started the car, NO more lights. No lights for at least 1 year. If the problem was the ABS/VCD ECU, I don't think it would work without issues for over a 1 year. A year later while going over a speed bump faster than I should have, the lights turns on immediately.
For some reason I just don't think it is the ABS/VCD ECU. this sounds more to me like a bad/loose speed sensor or a wire shortening somewhere. but all speed sensors appear to work correctly and show the same speed at all four corners.I did not see any where in the service manual where it suggest to change the ABS/VCD ECU.
Customer: replied 1 year ago.
is it possible for one of the speed sensor to be bad or have issues but still report the correct speed? I have driven for hours and logged the speed of all four sensor and all showed the same speed within 1 mph the whole time.
Customer: replied 1 year ago.
It is also common on the sedans to have some grounding issues with the wires in the trunk lid area where the grommet is. Mine were actually cut a while ago and I got the same lights (years ago)(only notices it because one of the brake lights did not work and neither did the light in the trunk. . but after I fixed them the lights went away. I checked that area again as much as I could but did not see any more cut wires.
Expert:  peterpete190 replied 1 year ago.
It is possible this is a shorted or damaged wire or the hydraulic unit,since you slammed on the brakes and the fault went away for a year if there was an issue with the pump/hydraulic unit you may have temporarily corrected it when you slammed on the brakes and now the fault is back again.Re-reading your info here I am leaning on the hydraulic unit as the cause.
If it was a speed sensor issue when the fault acts up you would see a speed signal difference right away on a scan tool.
Thanks Pete
Customer: replied 1 year ago.
assuming it's the pump/hydraulic unit like you are suggesting , how the heck is it throwing the c1142 pressure sensor circuit code? as far as I can see the 2003 G35 sedan does not seem to have any electronics and/or sensors in the pump/hydraulic unit and the pressure in the systems according to my scan tool looks good , according to the service manual.
Expert:  peterpete190 replied 1 year ago.
My info unfortunately isn't showing the code you have listed but if the hydraulic unit is not sensing or producing enough pressure it may set this code here.
Thanks Pete
Customer: replied 1 year ago.
The are literally 100's of these cases with Nissan and Infiniti cars throwing the C1142 code, from the G to Altimas, 350z, Armadas, etc. and you as a Infiniti mechanic don't know or show any info for the c1142 , it is really hard to believe.Are you sure you are Inifniti mechanic?
Expert:  peterpete190 replied 1 year ago.
I have worked on some of these models here before but saw your question did not receive an answer so I thought I would see if I could help.If you want I can open your question up for others here to see if anyone else can assist more on this just let me know if this is something you would like to do.
Thanks Pete