P1572

[ukrkoz]

2011 QX56
2 days ago cruise stopped working again. So far, cleaning radar worked every time, but not this time.
Not my question.
I replaced both brake pedal switches with OEM Nissan off Amazon. October last year.
Today, because of the CC issue, I scanned the car and got all kinds of codes. One of them is P1572.
Internet says it's brake switch. Brake lights turn on just fine. Car starts just fine. I checked on switch, it's solid in place.
I mean, I can replace the switch, no big deal - but what the heck?

[ukrkoz]

I looked at FSM and there is no P1572 in brakes section. All codes there are C-codes.

[VStar650CL]

That's because the engine (ECM) monitors the cruise brake switch, not the ABS. Look at EC-443 here:
https://www.nicoclub.com/service-manual ... 1%2FEC.pdf

P1572 indicates either a conflict between the cruise and brake lamp switches or a dead cruise switch signal. Since both are new, one or both may be misadjusted or have a mechanical issue. If not, you may have a wiring issue.

[VStar650CL]

PS - Blown fuses can also cause this, although there will usually be BCM/ABS codes if that's the problem. If your scanner can't read those systems, make sure you have brake lights and check fuse #3 in the cabin fusebox.

[ukrkoz]

Thank you.
Brake lights work fine.
No ABS codes. I have BCM code for aftermarket key ever since I own the car.
I checked switches manually and they both appear to be solid in place and no wiring issue.
OK, I have to take back ABS statement.
I had C1142 ABS code, Pressure sensor circuit.
Also, I had:
C1A14
C1A06
C1A16
C1A04
C1A26
C1A16 BEING SONAR CODE.
Question: as every time before, I had CC stop working, I cleaned sonar and CC came back to life - had to do this about once a month - do I have bad sonar? I know for sure, this vehicle was ibn salt water, judging by amount of rust.
I'm leaning towards replacing sonar with used unit. Also, cleaned it again with stronger cleaner and wiped off real well. CC warning light BEFORE would come up right away after cruise turned on, it did not after cleaning.
I deleted all codes yesterday, but did not drive the car, don't want to get stranded. I rescanned system about 2 hrs later, those codes did not come back, but, again, car was not driven. I'll drive it tonight, will see, what happens. Just in the hood.

[VStar650CL]

C1142 is one of those codes where the ABS is blaming the wrong thing, it's almost always caused by a bad brake lamp switch or the cruise and lamp switches being out of synchronization.

C1A14 is derivative and means nothing, it was the ABS reacting to the ECM not sending an engine speed signal after throwing the P1572.

C1A06 is also derivative and meaningless, it's for the ADAS seeing the cruise switch on the wheel "on" but the ECM not confirming it.

C1A16 is NOT a sonar code. It's for the front radar and simply indicates a blockage of some sort. The code happens all the time and will clear itself when the blockage clears, the most common causes being light rain and bug splats. It can occur frequently if the radar is mis-aimed or the bracket is damaged.

C1A04 is also derivative and means nothing, it was the ADAS reacting to the ABS not sending a vehicle speed signal after throwing the C1142.

C1A26 is an internal ADAS self diagnostic but will usually clear itself and often shows up with derivative codes affecting ABS and ADAS. I.e., it probably also means nothing.

Your underlying problem appears to be entirely in your brake switches. The radar blockage is a separate issue and may not mean anything, but since it will disable the intelligent cruise while it persists, it may be contributing to your perception of the issues.

[ukrkoz]

Thank you so much, VStar.
Basically, you saying, go get switch from dealer and replace it. Instead of buying one online.

[VStar650CL]

Online ones are usually fine, but I'd definitely try a different brand than whatever you bought. Also check that there isn't anything mechanically wrong with the pedal stops that's causing the switches to land in different positions. They need to be synchronous both mechanically and electrically.

[VStar650CL]

PS - I'd also hit InfinitiPartsDeal with your VIN and get the factory part numbers for both switches, then use those to shop. That will limit the possibility of getting a lookalike switch that isn't right for your ride.

[ukrkoz]

I got switch from Nissan dealer. I'm beat, getting old, will get to it either tomorrow night or Saturday early am, I do well in the mornings. I hope, it's just the switch. Amazing, how much havoc it caused across the modules and more so - there's no CEL.

[AZhitman]

VStar is a national treasure.

[VStar650CL]

I got switch from Nissan dealer. I'm beat, getting old, will get to it either tomorrow night or Saturday early am, I do well in the mornings. I hope, it's just the switch. Amazing, how much havoc it caused across the modules and more so - there's no CEL.

Hope you got both switches, either one can cause P1572. It's usually the result of either worn contacts in the brake lamp switch causing an internal loss of synchronicity between throw 1 and throw 2, or worn contacts in the cruise switch causing a loss of synchronicity between the two switches. So for that particular code, replacing both is called for.

[ukrkoz]

Well, to bad too late. Got one so far. We'll see. After all, both current ones are only 8 mths old.

[ukrkoz]

Darn. Cruise switch to be ordered only. 25300-AT300 speed cut off switch.

[ukrkoz]

Update:

1. replaced brake (light) switch with OEm one. Indeed, OEM one was VERY different from Amazon one.
2. re-did all height adjustment procedures
3. OEM air bags hold well, no air leaks.
4. took truck for a drive shopping. About 25 miles one way, so it did drive cycles.
5. plugged scanner in. All codes are gone except
- height adjustment sensor down came back
Hence, compressor will not initiate on its own.
While sitting in parking lot, with scanner plugged, found a whole bunch of various height adjustments, so ran all of them.
As the result, rear came up, as it should.
I'm cheap, I'll just keep scanner in the truck and manually re pump bags once a week. Takes less than 5 minutes.


That brings me to a question.

HOW LONG CAN/SHOULD COMPRESSOR RUN? It does not sound strained even after a minute of operation and, besides burning compressor, I don't want to blow air bags.

[VStar650CL]

The compressors have a fairly hefty motor but a fairly weeny pump, so it's not unusual for them to run awhile when they need to pump up a flat rear. I wouldn't worry too much as long as it eventually cycles.

[ukrkoz]

Thank you again.
How do I test height sensors? I know to unbolt the arm and trip it manually. Unbolt arm> rotate counter clockwise 2 times> bolt back on> see if this trips compressor. Anything else I can do? At this point, I'm getting suspicious of bad height sensor. Also, does engine have to run to trip compressor with sensor, or it can be in Aux? I really want to get this issue solved and forget about it, truck been on the lift every weekend now.
BTW, does it have independent rear air bags, or compressor pumps both same time? Then, lower side will indicate bad sensor.

[VStar650CL]

The compressor pumps both in tandem. The active suspension option (HBMC) is the system which can actuate each wheel independently, and those are all-hydraulic. I don't recall if the pump will run in Accessory or not, but I suspect it needs Ignition.

You can check if the sensor is good by ohming it, it should read very close to the listed values if it's healthy. See SCS-71 here:
https://www.nicoclub.com/service-manual ... %2FSCS.pdf

[ukrkoz]

Got it. I can log into sensors with scanner. Correction: no, I see, sensor has to be removed for Ohm check.
Yes, mine has that hydraulic system with high pressure pump running oil across all four corners. If that's the same as HBMC I don't know. All I know it is next to impossible to service it without special dealer equipment and that's $900 with tax around here.

[VStar650CL]

Yah, that's HBMC. IIRC it stands for Hydraulic Body Motion Control. However, it won't act to jack the vehicle, it's a reactive system that acts to maintain XYZ stability of the body in response to road conditions.

You can display the voltage from the sensor on a good scanner and that will tell you if it's moving, but it won't tell you if the voltage is right for the height. Ohming the sensor top and bottom will tell you if it has the correct span and isn't lying to the controller.

[ukrkoz]

OK, didn't have sensor off but had scanner hooked up during live feed, while driving.
Sensor is live, it posts anywhere between 2.4 - 2.88 V. Now, is that good voltage or not, that I do not know.
Comp still does not come up on its own. I keep tripping it with scanner to inflate air bags. .
NO ESUS codes for the last few days.

[VStar650CL]

Trouble is the FSM doesn't give you voltages, just resistance. Because there's a fixed resistor in there, Ohm's Law can't tell you what the voltage should be without having a schematic for the sensor's internal circuit. So the only way to know if the sensor is right internally is to ohm it.

[ukrkoz]

CC turned off again.
I have OBD port extension installed now and plugged scanner while driving.
It pulled C1a14 code. Apparently, front radar, as I suspected. Considering that I have to clean it every month and last time cleaning lasted only 2 weeks, and I'm to really driving in mud and it was not heavy raining, I vote it's radar.

[VStar650CL]

Radar can cause C1A16 but not C1A14. C1A14 is thrown by the ADAS Unit (not the ABS) when it can't get the pedal position from the ECM. If there was no code in the ECM then your ADAS Unit is probably dying. You can see the diag path on CCS-103 here, it basically says if there are no engine codes and no CAN outages then replace the ADAS C/U:
https://www.nicoclub.com/service-manual ... %2FCCS.pdf

[ukrkoz]

Huh. Online search said radar.
No, I don't doubt you, you know your stuff. It's just cleaning radar restored CC every time, so it was easy to 2+2 together. I'll see, what will happen tomorrow. Will delete code and go for regular drive.
Pity. Crap starts building up. And it's around $8000 car if to sell, so spendy repairs and parts are out of question.

[ukrkoz]

OK, so I can't delete code. Tried several times.
Where exactly is that ADAS unit located? Internet no help, it talks about multiple units being part of it.
Also, can I just unplug radar and still use CC? It's very handy. I can do without but rather not.

[VStar650CL]

The ADAS is underneath the lefthand cargo area trim. Not easy to get at.

See if your "emergency dumb cruise" will work. Hold down on the on/off button for about 2~3 seconds. On almost everything Nissan, that cancels ICC and gives you a regular CC.

[ukrkoz]

Nope. Throws CRUISE light in the dash, I tried it yesterday. Can I simply unplug radar and have dumb working CC?

[VStar650CL]

I don't think so. The ABS and ADAS both still need to have communication or the cruise will shut down entirely, and unplugging the radar will usually cause the ADAS to go offline.

[ukrkoz]

As of today, CC does not work at all. Before, at least that button that illuminates green light and keeps distance to the car in front and corrects lane departure worked. Now, either button throws CRUISE light in the dash.
No other issues with driveability.
Got a schematic where that ADAS is exactly?