drewsome2

Anyone have this problem, or know where to even begin? Was driving about six weeks ago, car kind of stumbled, ABS & ASR lights came on - no check engine light. Tried to pull codes - nothing. Left the car running because the serpentine was making god-awful squeal - pulley on H2O pump wobbling back and forth. So replaced water pump and put on old serpentine belt. Ran car again, ABS & ASR lights on again. Thought perhaps belt was stretched, so got a new one. Lights still on - car runs nominally when it they are on, though. I have checked battery and alternator output, as manual says that those lights will come on if voltage slips below 10. Both are okay.

But those lights are still on most of the time (there are some times when they are not on, and the car shifts terribly when they aren't on!), and I have no clue where to look next. It is also starting to drive "squirrelly" - almost like driving in a big wind storm. The car sometimes suddenly pulls to one side or the other.

Another interesting problem - once I put the new belt on, it started with the surging again - so bad that it actually cut out on me once. But (get this!) unplugged the MAF sensor, and it evened out. I'm thinking O2 sensors....

Anybody have any suggestions, ideas, clues as to where to go from here?

ohlord

should be about 14.5 volts. triggering the lights when abs light is on the power is cut back and on some models trips the limp mode.
common causes
faulty brake switch
faulty maf sensor try cleaning it with crc brand maf cleaner
alt output
battery
O2
cat
abs relay failed

drewsome2

That's a great start! Let me tell you what I have already checked/done:

• replaced MAF about 6 months ago <?>
• alt output is 14.7
• battery output is 12
• replaced front brake pads just prior to this problem occurring - could I have messed up brake switch in doing so?
• haven't checked O2 sensors - could that really be the cause of all my problems ?!!

Is the car safe to drive while in "limp" mode while I travel through the rest of these items on your awesome list of other things to try? I had benched it, but it seems like it runs fine (with exception of occasional engine surge) so I have been driving it for the past few days.

Thanks soooo much for your help and advice!

StapleGun

All 'ohlord's' info is spot on - I researched a little bit this morning, I could not find the exact location on our car (C43), I'll get under it tonight and confirm. It is a possibility that it's the ABS speed sensor kickin' in and out (possibly on differential).

ohlord

it is more of a reduced power mode then an actual transmission lower gear limited limp mode ,if so it is okay to drive,just remember though with the lights on you have no abs so don't over drive it.
also check all vac lines.
I hate when these no code issues come up because they are so hard to track down.Where did you get the maf?Is it a real bosch maf or off ebay?

MBHustla858

whats the condition of your engine harnesS?

99MBSport

How is the cruise control?? If that is not working all points to the Brake light switch at the brake pedal. Tis would also cause the squirelly movements to as the ASR will not be working.

drewsome2

to ohlord: The MAF is off ebay - got it in January 07.

to MBHustla858: Replaced the wiring harness in May 07 - fried my ECU. So, have new ECU too.

to 99MBsport: cruise control works when lights are not on. When ABS/ASR lights are on, nothing.

Today the lights didn't come on at all, and she drove like a champ. No squirrelly movements, cruise control worked, etc.

svt ricco

why not have it checked by a pro? just a suggestion