[Blue Angel]

I wonder why the automatics have an issue and not the manuals? I wonder what all is different with the brakes?


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[Blue Angel]

Sounds like it may be for those who drive an auto with both feet on the pedals at the same time.


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[Blue Angel]

I'd be interested to know the part number of the suspect microswitch and see if matches what we have downunder.

It very well could be the same part from the same company. Recalls are usually a regional thing, though, because by the time a recall is issued there is usually very little that is NOT known about the problem. It may have been a bad batch of parts that got into circulation, and though QC tracking methods they are able to track the suspect parts through the network and find out when and where they were used. If that's the case here, they will feel confident that they have identified the models affected and where they were built.

This could also NOT be the case, and maybe a completely new switch is required (likely here since ALL vehicles with the switch are recalled). Maybe they changed to a different switch to alleviate the problem, and some time after that the issue grew "popular" enough with the Feds that a recall was deemed necessary. If this is the case we will probably never know what the issue with the switch was... maybe QC, or maybe design related. All we will know is that there's a new part number that supersedes the old one.

Even if it is the same switch used in Aus, there may not be a recall in that region based on statistics... it may never grow to be a large enough issue, or it may not be an issue at all. Example, if the reason for the switch malfunction is related to the operating environment it's possible there would be no failures of the switch in Aus. These are usually complicated issues, and the public is never made aware of all the gritty little details that go into making the decisions.

 

[Blue Angel]

This is probably not a cold start issue, this is probably a high idle issue. High idle is most common when cold starting and that's likely the reason for the association.

Any time the computer commands a high idle, like 1500 RPM, the engine will struggle against the torque converter to get the engine to that RPM. In a small turbo engine like this the manifold vacuum will drop and the power assist to the brakes will suffer. That's where the auxiliary vacuum pump comes into service, but if the switch fails to activate the pump, well, no power brakes.

Chances are, replacing the switch with a new one of the current design will fix the issue since few Cruzes actually have the problem to begin with. This should be seen as a good short-term remedy until the revised switch is available through the recall. If I had a car with this issue I would call the dealer and ask them to tow the car in (if you don't feel safe driving it in), replace the switch, then assuming the problem is temporarily cured, drive the car until the recall notice comes and then have them perform the recall.

In any case, I would imagine putting the transmission in Neutral would "avoid" the issue in two ways; 1) the car would be unable to propel itself forward, and 2) it would allow manifold vacuum to build, restoring power assist to the brakes.

 

[Blue Angel]

PM sent.

Let us know how things work out.

 

[Blue Angel]

The difference will be that the manufacturing of this switch will have been modified to prevent the silicon and other whiskers that are causing the switch to short out and not operate. These whiskers are electrically conductive and allow current to jump from one part of the chip to another part.

Cool! I've heard of whiskering before (Tin Whiskers):

Whisker (metallurgy) - Wikipedia, the free encyclopedia

 

[Blue Angel]

Even with the engine off but the key in the run position I have full and repeated braking with no increase in pedal pressure required.

Yes, it would seem there's a vacuum pump in the MT cars as well. If coasting with the engine off you can actually hear the pump come on every time you press the brake pedal to keep the vacuum up. Neat feature... I wonder if this is implemented for regulatory reasons (i.e. everybody's doing it) or if it is to adress a Cruze-only quirk?

 

[Blue Angel]

Good info Rob, thanks!

 

[Blue Angel]

My brake vacuum assist is getting flaky on my manual transmission Eco. It was nice having endless brake vacuum when I needed to coast slowly for a long period. This morning it started working again when backing out of my driveway.

I'm assuming it's the switch since the pump seems to work OK once activated. I wonder if they will replace the switch on a manual car?

 

[Blue Angel]

FWIW, my '12 Eco MT has this same issue. Since there's no automatic transmission to drive the car ahead while my foot is on the brakes, there's no safety issue, BUT the switch has failed none the less and the vacuum pump brake assist is not working.

While this may only be a safety issue on automatic equipped cars, the pump is there and is intended to function on manual equipped cars as well.

I have not planned to get my dealer involved in fixing this yet, but when I do I will update the thread.

Changing those parts fixed the symptoms and my brakes are back to normal...

Does your invoice happen to state the part number(s) replaced? I would be interested in getting the price of the parts. If they're less than ~$50 I would likely just change them myself rather than deal with an all day dealer visit.

 

[Blue Angel]

Let me try this again a little larger...

Thanks a bunch!

So it looks like they only listed the part number of the hose, not the switch?