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ABS / PSM Lights - Brake Light Switch

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Old 12-24-2006 | 10:32 PM
  #16  
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Thank you very much for the offers to help! I am going to stop by Autozone to get the codes read and then report back.

I hope all of you have a very, very Merry Christmas!

Doug - I owe you a long overdue apology for dropping the ball on the seat cushions earlier this year. I was traveling A LOT for work and never had a chance to make it north. I sincerely appreciate the offer. How is the diagnostic software you bought working out?

Jeff

Last edited by jdk1; 12-25-2006 at 12:53 AM.
Old 01-09-2007 | 11:49 PM
  #17  
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I ordered the Durametric cable and software early last week and it arrived today.

ABS Code:
Fault Number: 4340
Description: Stop-light switch
Repair Infomation: Check input signalsThere was also code:

DME Code:
Fault Number: P1574
Description: Factory Fault Code 364 - Stop light switch
Repair Infomation: Signal implausible

The lights were not on when I downloaded the codes. As I mentioned, they appear every time I drive the car the first or second time I step on the brakes after moving.

Any ideas? It seems like it still may be the switch that I replaced. It it possible that I got a bad one or broke it during installation? The brake lights work perfectly.

Jeff

Last edited by jdk1; 01-10-2007 at 12:12 AM.
Old 01-10-2007 | 01:39 AM
  #18  
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are you sure you replaced the right switch ?
Old 01-10-2007 | 01:46 AM
  #19  
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Had the same issue on a BMW 325 and it was the "pedal position sensor" which is located on the brake master cyl on a BMW....for what it is worth....
Old 01-10-2007 | 01:53 AM
  #20  
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I sure hope so.

The switch I replaced had a brown body and was mounted in a bracket facing the pedal. The switch gets pressed in when the pedal is released.

Is there another one I should be looking at?

Jeff
Old 01-10-2007 | 10:07 AM
  #21  
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sounds right you replaced the one on the brake pedal and not the clutch pedal correct?
try pusing the brake and pulling the switch out all the way and letting the pedal adjust it
Old 01-10-2007 | 10:58 AM
  #22  
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Well, I am in the same boat with a 2000 C2. Short version - ABS/PSM lights, cleaned MAF, lights went away. Few hundred miles later, ABS/PSM lights. Cleaned again, still the lights. Ordered new MAF. While waiting, but still driving car, got a CEL, P1128. Cleared that out, and the ABS/PSM light are still on, but no other fault codes.

Read a thread on this board, had the wife check the brake lights, and my center brake light works, but the corner brake lights don't. CEL came back on again. Same fault code P1128.

Installed new MAF, cleared the CEL, but the ABS/PSM light remain.

Waited til middle of the night, cranked up the car, drove all around my area, but did not use the brakes. No ABS/PSM lights. Various rpm ranges, up to 80 miles an hour, everything is cool.

Touch the brakes and as soon as you release the pedal, ABS/PSM lights up.

PSS9's to be installed next week. I am going to have those guys figure it out.

But, I did do the Ipod hack over this weekend. Now, I can't get the keys out of the radio. Gonna let the pros handle that one too.
Old 01-10-2007 | 11:37 AM
  #23  
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1128 isnt brake related, its fuel mixture related most likey if you look at your adaptaion values you will find that they are negative incating a rich mixture.
at that point you check fuel pressure and its going to be ok, you will need a new maf sensor,
Old 01-10-2007 | 12:16 PM
  #24  
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Brad -

Thanks again for following this thread and offering your insight. I drove to work this morning and ended up getting a CEL on the way. I had the Durametric cable in the car so I got the codes before I shut the car off. As of this morning these are the codes:

moduleType = MotronicDME72
dtcCount = 3

Fault Number: P0446
Description: Factory Fault Code 95 - EVAP canister shutoff valve (function)

Fault Number: P1574
Description: Factory Fault Code 364 - Stop Light Switch
Repair Infomation: Signal Implausible

Fault Number: P1130
Description: Factory Fault Code 361 - Oxygen sensing adaptation, idle range, bank 2

9X6 ABS 5.7 Selected

Fault Number: 4340
Description: Stop-light switch
Repair Infomation: Check input signals

The EVAP and O-sensor codes are new as of this morning. I don't know if they are related or not.

Thanks again for the help.

Jeff
Old 01-10-2007 | 03:13 PM
  #25  
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DME 7.8
9436 P1574 0-190 page 1
DME 7.8
p1574
0
Printed in Germany, 2000
0-190 P1574
364 Stop light switch - signal implausible
Diagnosis conditions
• Ignition on
Possible fault cause
♦ Stop light switch
♦ Wiring harness
The DME control module receives the signals from the stop light
switches via CAN bus.
Affected terminals
Diagnosis/troubleshooting
Note!
Work instruction Display OK If not OK
1 Check stop light switch ♦ Remove stop light switch
♦ Measure resistance between Pin
1 and Pin 4
0 - 5 Ω Replace stop light
switch
→ End
♦ Actuate stop light switch ∞ Ω
♦ Measure resistance between Pin
1 and Pin 2
∞ Ω
♦ Actuate stop light switch 0 - 5 Ω
♦ Install stop light switch ⇒ Step 2
2 Check wiring from PSM
control module to stop
light switch 1 for short circuit
to B+
♦ Remove PSM control module
connector
♦ Measure voltage between Pin 32
and ground
♦ Switch on the ignition
0 V Repair wiring harness
→ End
♦ Actuate brake Battery voltage
⇒ Step 3
DME 7.8 DME 7.8
0-190 page 2 9436 P1574
p1574
0
Printed in Germany, 2000
3 Check wiring from PSM
control module to stop
light switch 2 for short circuit
to B+
♦ Remove PSM control module
connector
♦ Measure voltage between Pin 37
and ground
♦ Switch on the ignition
Battery voltage Repair wiring harness
→ End
♦ Actuate brake 0 V
→ End
Work instruction Display OK If not OK



the 1130 is most likey the maf sensor but you need to check the adaptaion values to be sure the 0446 could be related to that, ID CLEAR THAT ONE AFTER THE OTHER FAULTS ARE FIXED and see what happens
Old 01-18-2007 | 07:56 PM
  #26  
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It turns out the new switch was faulty after all. I bought a multimeter at Sears and took the measurements that Brad suggested. It turns out that there was a problem with the 1-2 pin connection. I took the switch apart and reassembled it carefully. Sure enough, after reassembly the readings were correct. A test drive confirmed that the problem is solved.

Thank you again for all of your help.

Jeff

Last edited by jdk1; 01-20-2007 at 05:14 PM. Reason: Edit: Problem Solved



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