VSC, ABS, BRAKE, ((!)) --- Is brake pedal stroke sensor responsible?

In your earlier thread on the same topic, after clearing up that you can connect pins 4 and 13 to read the onboard diagnostic information (and not just to reset it, which is more like shoot-the-messenger), you turned out to have C1253/53, C1256/57, C1242/42, and ?????/45 (we didn't find the 45 blink code in the manual, which happens sometimes; the manual seems to have some gaps on the blink codes, and also I was looking in a 2006 book, not your 2005).

The C1253 pertains to a problem with one of the two pump motor relays supplying power to the pump. Unfortunately, the blink method does not give INF codes. There are seven possible for C1253, which would paint more of the details, but I would bet you had INF code 134, meaning the system energized pump relay 1 and saw no power arrive, and I would bet that way because that's where you found the blown fuse.

The C1256 pertains to the system failing to pump up enough pressure to assist you with braking. That is not especially mysterious when a fuse supplying the pump is blown.

C1242 refers to a problem in one of the two power source circuits that start with the brake capacitor box in the back of the car, and supply the skid ECU and actuator. That might be a separate issue from the C1253/C1256, but it is possible that old corroded wiring or connectors could be a common factor to both.

If I may ask, where did you dig that suggested the stroke sensor? I noticed you mentioned it in the older thread too, and found a code for it in the manual, but that isn't any of the codes your car is giving you.

You've mentioned hearing the brake alarm sound. That doesn't happen for things like stroke sensor issues; the alarm is reserved for things like hydraulic pressure issues that will impair your control of the car.

Faulty wiring is still a viable suspect. So is a worn-out pump in the actuator. The wiring possibility is more appealing from a parts cost and labor perspective, so by all means don't overlook that possibility, but understand that which problem it turns out to be is going to be ... whichever it turns out to be.

Blown fuse doesn't really qualify to be the problem in its own right. You had a blown fuse, and that shows unmistakably that there is a problem ... somewhere else. The task remaining is just to find what that problem is.

That might move the "faulty wiring" possibility a little lower in likelihood, I'm sorry to say. Ordinarily, corroded wiring connectors will deliver less power than needed, but to blow a fuse, something must usually consume too much. That's more likely to be a worn-out pump. But don't give up on wiring until you've checked; if there is insulation damage and a wire bumped against a ground, that could also show up in a blown fuse.

Have any new trouble codes appeared, or any of the original ones not reappeared, since you changed that fuse?

 

Hang on though. Your actuator is a box with an electric pump, an accumulator chamber, ten electrically controlled valves and a mechanical one, and seven pressure sensors. There's a lot more than one way for it to go bad.

In the video you found, somebody had an actuator where the pump was just running constantly ... probably because one of the valves no longer seals well, and the fluid pumped up by the pump was just flowing right back to the reservoir, and pressure never built up. That's one way an actuator can go bad. Yours doesn't sound like that, so it hasn't gone bad that way.

You could have a tired pump, that runs feebly, or runs intermittently, or draws too much current and eventually blows a fuse and then doesn't run at all. That could still give you inadequate pressure and a code for that, even though it would not sound like the one in the guy's video that failed a different way. It would still be an actuator replacement, in a Gen 2, because the actuator, accumulator, and pump are all one assembly in that generation.

You have heard the buzzer, you reported it earlier. If it isn't sounding right now, that's a good thing, but it only sounds right when certain conditions exist. It is a "something is definitely wrong if I'm sounding" buzzer, but it isn't an "if I'm not sounding, everything is hunky-dory" buzzer.

As I said in the earlier thread, it's usually not a good idea to shorten, generalize, or paraphrase about what a particular code means. If you have a 57 code, that either means there was a moment when you were driving, you used the brakes, and less than 12.45 MPa pressure was available at that moment, or it means there was a moment where two solid minutes of the pump being called for did not raise the pressure to at least 14.62 MPa. A trouble code never really tells you what is causing a problem, or what you need to do about the problem; it can only tell you what it saw. For code 57, one of those two things is what it saw. (If you had Techstream, you could read the INF code and then even know which of those two it was. You would also be able to Data List the pressure sensors and see what the pressures actually are—or see a questionable pressure and explore whether a sensor is flaky. You could pull up the freeze frames and see exactly what was going on at the moment each code got set. You can kind of see why people use Techstream.)

As for the C1242, if I remember right there are several pages of workup steps in the manual that should be able to guide you through troubleshooting that. Looked like you would need a multimeter and it might be tedious to get to some of the connectors where they would have you test, but that's how it goes sometimes.

 

If you're not looking in the manual yourself, and being guided by the suggested workup steps there, you could have a long drawn-out diagnostic slog ahead of you, with detours and cul-de-sacs where you get cooler instead of warmer.

 

Yeah, that seems odd to me too. But it's probably something they know how to do, so they decide the problem must be the thing they know how to do.

Doesn't happen only at Meineke....

 

Did the dealer offer you a solution after the 'scan', if so could you please post it here and in the other thread you've abandoned.

Was a 'mini-vci' cable and techstream not an effective solution for you, the cost is about 1/10 what the above dealer is charging.

 

Hello dhman2006 how was this resolved? The last post you mention getting your car scanned at the dealership. Did you fix it or scrap it?