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"Brake Failure" P0571 and P0504 Topic is solved

Help, Advice, Owners' Discussion and DIY Tutorials on Volvo's stylish, distinctive "P2" platform cars.

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Marcobrick
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"Brake Failure" P0571 and P0504

Post by Marcobrick » Fri Mar 08, 2019 12:16 am

Hi all. I’ve been absent from the forum for a couple of years in the Volvoless wilderness. I’ve recently been reading topics on the XC90 as I was sure I was going to buy one. I did however buy a 2002 V70 T5 in a lovely electric blue colour. Naturally it comes with a few faults the most vexing of which is a brake system fault.

There are some great writeups on the site regarding various ABS faults. I cannot find any that match my symptoms exactly.

Here’s what I have:

Brake Failure stop safely on the information panel
Orange warning triangle
Red brake light
ABS light
Amber stability control light (My car does NOT have DSTC)
I have an odometer presentation but the mileage is not increasing
Dashed lines where my trip information should be.
The speedometer DOES work normally
The transmission IS behaving correctly
I have normal and reliable brake light function and shift lock function

I only have an Innova 3130 CAN OBD scan tool and it picks off P0571 brake switch citcuit A and P0504 brake switch A B correlation. I can clear the P0571 but it comes back.

Earlier today I disconnected the battery and unplugged and contact cleanered(I’m sure that’s a verb) the ecu connections and the brake pedal position sensor plugs. When I reconnected the battery, started the car and cleared the codes, i drove it for 200 meters with everything working and no lights. After shutting off and restarting they all came back.

If I unplug the brake pedal position sensor (on the booster) it changes nothing and no new codes appear.
Would I be wasting my time (and money) changing this sensor?

The other item of suspicion is the BCM but that’s even more money. In New Zealand we don’t have a lot of electronics repairers that take on this sort of work and those that do charge accordingly!

I don’t have access to VIDA unfortunately without going to the dealer and the local dealership are unhelpful thieves.

Suggestions please...


The Fleet:
2003 V70 T5
2014 Nissan Leaf
1973 Fiat 125
1970 MGB GT
Previously:
1996 850R sedan
1994 850T5 Sedan
1995 850 Turbo Wagon
1998 V70T5

Favourite line: "How hard can it be?"

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RickHaleParker
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Re: “Brake Failure” P0571 and P0504

Post by RickHaleParker » Fri Mar 08, 2019 1:50 pm

I would look for wiring defects first.

P0571 = Brake pedal position sensor. Either the Brake pedal position sensor or the wiring.


P0504 = ECM-510F Vehicle speed signal

Diagnostic trouble code (DTC) information

Condition
Diagnostic trouble code (DTC) ECM-510F (no signal) is stored if there is no communication between the ABS/brake control module (BCM) and the engine control module (ECM) or if the communication is distorted.An error message is sent to the engine control module (ECM) and diagnostic trouble code (DTC) ECM-510F (signal too high / too low) is stored in the engine control module (ECM). Diagnostic trouble codes (DTCs) for the vehicle speed sensor (VSS) signal are stored in the ABS / brake control module (BCM).

Substitute value
The vehicle speed signal from the ABS / brake control module (BCM) is set to 0 km/h

Possible source
Signal too high / low:
  • defective vehicle speed signal to the ABS / brake control module (BCM) A diagnostic trouble code (DTC) is stored in the ABS / brake control module (BCM).


Signal missing:
  • contact resistance in the Controller area network (CAN) terminals
    open-circuit in one or both CAN cables
    one or both signal cables short-circuited to ground, voltage or each other
    defective ABS / brake control module (BCM)
    defective engine control module (ECM).
Fault symptoms
Malfunction indicator lamp (MIL) lit.
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Marcobrick


Platform: P80 1998 C70, B5234T3, AW50-42, Bosch Motronic 4.4, Special Edition package, Plant: Uddevalla Sweden.

Platform: X40 (Nedcar) 2003 S40, B4204T3, AW55-50/51SN, Siemens EMS 2000. Plant: Born Netherlands.

Platform P2 2005 XC90 T6 Executive, B6294T, 4T65 AWD, Bosch Motronic 7.0, Plant Torslanda Sweden.
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1997 S90, B6304S, AW30-42, Bosch Motronic 4.4 - Sold

Marcobrick
Posts: 316
Joined: Tue Sep 28, 2010 9:44 pm
Year and Model: 2003 V70T5
Location: Christchurch,New Zealand
Has thanked: 3 times
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Marcobrick

Re: "Brake Failure" P0571 and P0504

Post by Marcobrick » Fri Mar 08, 2019 4:58 pm

Except that the speedometer works perfectly...


The Fleet:
2003 V70 T5
2014 Nissan Leaf
1973 Fiat 125
1970 MGB GT
Previously:
1996 850R sedan
1994 850T5 Sedan
1995 850 Turbo Wagon
1998 V70T5

Favourite line: "How hard can it be?"

Marcobrick
Posts: 316
Joined: Tue Sep 28, 2010 9:44 pm
Year and Model: 2003 V70T5
Location: Christchurch,New Zealand
Has thanked: 3 times
Been thanked: 0
New Zealand
Marcobrick

Re: "Brake Failure" P0571 and P0504

Post by Marcobrick » Fri Mar 08, 2019 11:15 pm

I removed the BCM today. It has been opened in the past. It’s different to the spare P2 bcm I have unfortunately, so I can’t play Swapsies. Presumably it has been re-soldered.

Also when I clear P0571, the P0504 disappears too. Went to the local Pick-a-part today. They have a V70 turbo but somebody has beaten me to the brake pedal position sensor!


The Fleet:
2003 V70 T5
2014 Nissan Leaf
1973 Fiat 125
1970 MGB GT
Previously:
1996 850R sedan
1994 850T5 Sedan
1995 850 Turbo Wagon
1998 V70T5

Favourite line: "How hard can it be?"

Marcobrick
Posts: 316
Joined: Tue Sep 28, 2010 9:44 pm
Year and Model: 2003 V70T5
Location: Christchurch,New Zealand
Has thanked: 3 times
Been thanked: 0
New Zealand
Marcobrick

Re: "Brake Failure" P0571 and P0504

Post by Marcobrick » Mon Mar 11, 2019 12:00 am

I know this fault knocks out the cruise control, but does it also prevent torque converter lockup?
Brake pedal position sensor is on its way.


The Fleet:
2003 V70 T5
2014 Nissan Leaf
1973 Fiat 125
1970 MGB GT
Previously:
1996 850R sedan
1994 850T5 Sedan
1995 850 Turbo Wagon
1998 V70T5

Favourite line: "How hard can it be?"

precopster
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Re: "Brake Failure" P0571 and P0504

Post by precopster » Mon Mar 11, 2019 5:29 am

The brake pedal position sensor is essentially the same unit as fitted to the 850s and there was a write-up here on MVS on how to repair it. The casing is a little difficult to pry open but once done there is a small contact board at the top that needs to be re-soldered.
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Marcobrick


Current cars:2002 XC70, 2006 Ssangyong Rodius (Stavic), 2006 XC90 2.5T, VW Transporter 2.5TDI

www.precisioncarmodules.com.

Marcobrick
Posts: 316
Joined: Tue Sep 28, 2010 9:44 pm
Year and Model: 2003 V70T5
Location: Christchurch,New Zealand
Has thanked: 3 times
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New Zealand
Marcobrick

Re: "Brake Failure" P0571 and P0504

Post by Marcobrick » Mon Mar 11, 2019 1:21 pm

I found the write up. Thanks! Maybe I’ll give it a go later this week when I’m off work. I have nothing to lose I guess.


The Fleet:
2003 V70 T5
2014 Nissan Leaf
1973 Fiat 125
1970 MGB GT
Previously:
1996 850R sedan
1994 850T5 Sedan
1995 850 Turbo Wagon
1998 V70T5

Favourite line: "How hard can it be?"

Marcobrick
Posts: 316
Joined: Tue Sep 28, 2010 9:44 pm
Year and Model: 2003 V70T5
Location: Christchurch,New Zealand
Has thanked: 3 times
Been thanked: 0
New Zealand
Marcobrick

Re: "Brake Failure" P0571 and P0504

Post by Marcobrick » Wed Mar 13, 2019 5:13 pm

This morning I removed the brake pedal position sensor. I replaced it with one from an XC90 that had no ABS warnings. The problem has not gone away. I then opened up the original (yep, it’s tricky and hard work while trying not to wreck it) I have cleaned the insides, re-tensioned the wipers and re flowed the solder on the board. I’m waiting for the sealant to cure and then I’ll swap it back in.

IF this is the part causing the problem, is there a special reset procedure to apply once a good(?) part is swapped in?


The Fleet:
2003 V70 T5
2014 Nissan Leaf
1973 Fiat 125
1970 MGB GT
Previously:
1996 850R sedan
1994 850T5 Sedan
1995 850 Turbo Wagon
1998 V70T5

Favourite line: "How hard can it be?"

Marcobrick
Posts: 316
Joined: Tue Sep 28, 2010 9:44 pm
Year and Model: 2003 V70T5
Location: Christchurch,New Zealand
Has thanked: 3 times
Been thanked: 0
New Zealand
Marcobrick

Re: "Brake Failure" P0571 and P0504

Post by Marcobrick » Wed Mar 13, 2019 7:34 pm

After refitting the original "repaired" brake pedal position sensor (no joy) I have removed the BCM and taken the lid off to see what someone did in there last time. I see no evidence of soldering but the pins look to have been bent slightly. I came across the pin bending trick on a UK volvo forum but it doesn't seem like a sound enough "repair" to me.
IMG_0200.jpg
IMG_0200.jpg (445.5 KiB) Viewed 422 times
Does the inside of this look normal to any P2 experts out there? All my previous experience is with P80 cars and the insides of this one are a bit different.


The Fleet:
2003 V70 T5
2014 Nissan Leaf
1973 Fiat 125
1970 MGB GT
Previously:
1996 850R sedan
1994 850T5 Sedan
1995 850 Turbo Wagon
1998 V70T5

Favourite line: "How hard can it be?"

Marcobrick
Posts: 316
Joined: Tue Sep 28, 2010 9:44 pm
Year and Model: 2003 V70T5
Location: Christchurch,New Zealand
Has thanked: 3 times
Been thanked: 0
New Zealand
Marcobrick

Re: "Brake Failure" P0571 and P0504

Post by Marcobrick » Thu Mar 14, 2019 9:58 pm

The P.O has provided me with additional information. The brake failure message appeared while driving home after having the brakes bled by his local mechanic. I’m not sure how that can lead to a fault like this.


The Fleet:
2003 V70 T5
2014 Nissan Leaf
1973 Fiat 125
1970 MGB GT
Previously:
1996 850R sedan
1994 850T5 Sedan
1995 850 Turbo Wagon
1998 V70T5

Favourite line: "How hard can it be?"

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