[saab.story]

i hand cleaned all the ABS wheel sensors on both my 88 9KT and 95 CSE, but it didn't help. i get intermitent ABS light that may or may not stay on from any of the following circumstances:

1. big bump
2. light bumps (gravel roads especially)
3. wet days in the 88 9KT on the highway
4. no reason at all!

any theories? does the computer hold the ABS error code from the last cause? for both cars? or just the CSE?

 

[wherewolfe]

My ABS light came on recently while traveling in the hills of Kentucky during an all day rain.
I thought for sure there was a problem. I concluded that high moisture around the sensors might trigger them.

As soon as I parked the car for about an hour over a canopy, I started up and the ABS light did not come on again. Haven't seen it on since.
I know that the system is working alright since I had them checked. Very strange.

 

[saab.story]

did they take a error code for you when you had them checked?

 

[HAGGAG01]

gents, i have had the abs blues, diagnostic said that sensor was faulty, but due to intermittent fault was unsure, however bought replacement sensor, (4 mnths later no probs).
A saab specialist with the right gear should be able to diagnose.

 

[saab.story]

how did they determine which sensor!?!?!

 

[zeke]

An easy thing to check is the electrical connector that mounts on the side of the ABS pump motor (Mk II version). My '92 used to give intermittent ABS EDU lighting. I pulled the connector and shot a healthy dose of WD-40 into both ends of the connector. Seemed to be the cure for my intermittent ABS light.

 

[saab.story]

robert,

best idea i've heard yet on several boards! thank you...i'll check it on in a couple of days. the issue is very curious to that of poor connection that may need cleaned or repaired...

 

[Derek]

Unplug the connector and measure across the pins with a digital multimeter set to ohms. You should get a reading of about 1 Kilohm at each sensor. If you change the multi meter to ac volts and spin the wheel you should get a reading of a few 10's of millivolts, depending on how hard you spin the wheel. Most likely problem of an intermittent sensor is a break in the cable. The front N/S (driver's side in the US) is the most common culprit apparently.

 

[HAGGAG01]

Derek is right it tends to be that sensor, it was on my car. New sensor is dear, I got a 2nd hand replacement with guarantee for £35. A saab specialist may have the handheld computer that hooks up to the system, this can pinpoint the prob, it hooked up to a connecter under the drivers seat.

 

[markcanderson]

If you're not handy with a multimeter, but have a friendly garage willing to loan you a Saab TechII device.. you can do the following to determine which sensor is causing the problem.

The speedo on the 9000 etc.. is electronic and gets it's data from the ABS sensors. Plug in the TechII device (under the passenger seat) and on the device you can set it up to graph each ABS sensor's speed reading. And then go for a drive.

Any inconsistances in those four graphs, will highlight an inconsistant ABS sensor.

 

[billj]

Originally posted by MarkA:
[qb]The speedo on the 9000 etc.. is electronic and gets it's data from the ABS sensors.[/qb][/b]

Mark, the Tech II thing might work (I don't know), but it's nothing to do with the speedo. The 9000 speedo has a speed sensor mounted on the differential housing. It is the 9-5 that drives the speedo from a signal derived from one of the rear ABS sensors.

If you had a Tech II, wouldn't it be much easier simply to interrogate the stored fault code which will tell you exactly which sensor the ECU isn't happy with?

On the '88, I believe you will still have stored error codes. However, it may be that a separate ABS tester (not Tech II) must be used to interrogate it.

 

[adrian]

On an '88 do you not just jump a couple of pins to get the error code fashed out through the ABS light? Details on Townsend Imports site if I remember correctly. The '95 will need Tech2 to read the fault codes

 

[markcanderson]

Bill, I've used techII and seen on the screen the numerical ABS sensor readouts 1 through 4 (i.e. each wheel) indicating individual wheel speeds on my 9k.

The speedo may only use one of those sensors.. but all of the wheels speeds are captured electronically, (for TCS and ABS purposes)

 

[billj]

Mark, I don't for one second doubt that Tech II can do this, as I know it can plot many other parameters in real-time. However, on the 9000 the speedo doesn't use any of these sensors, but uses an electronic speed sensor mounted on the gearbox. This sensor directly replaced the mechanical drive cable when the electronic speedo was introduced on the 9000 in '86 or '87, before the introduction of ABS on 9000 turbo models and well before its introduction across the rest of the range.

I still think the best use of a Tech II to diagnose Shawn's problem would be to pull the fault code identifying the faulty sensor.

 

[HAGGAG01]

have to agree with bill,tech II is the only thing to solve this prob without any more heartache. I am not doubting the multimeter(elec eng to trade) but when I tested the abs sensor with the m/m after tech II (still in denial at this point)it showed it to be within parameters, however forum members assured me that the tech II was correct and to fit new sensor. Took there advice and hey pesto !!

 

[markcanderson]

Bill.. I'm not talking about the speedo reading.. I'm talking about ploting the ABS sensor speed readings from all 4 hub sensors. If one of the sensor readings is constantly falling off in the graph.. then there's your faulty sensor. On cars this old.. the fault codes are usually not worth beans... I know I've been tracking a TCS problem for 6 months.. and everytime a completely different set of fault codes on TechII.

 

[billj]

OK, Mark. I was sure you said that the electronic speedo ran from a signal from one of the ABS sensors.

Originally posted by MarkA:
[qb]On cars this old.. the fault codes are usually not worth beans... I know I've been tracking a TCS problem for 6 months.. and everytime a completely different set of fault codes on TechII.[/qb][/b]

The TCS is a complicated beast and I don't doubt what you say about the fault codes. It is notoriously difficult to diagnose. However, I have never heard anyone complain that the ABS fault logging is unreliable. Compared to the TCS, it is a fairly straightforward system and seems to have been implemented quite well right from the start.

I'd still give the codes a chance. If the ABS light is intermittent, you could travel miles without triggering it (and seeing a dropout in speed reading from one of the sensors). And I'd be pretty sure you can't do that on an '88 anyway. The codes will remain stored, even if the problem hasn't occurred for a while.

 

[adrian]

Townsend Imports

Above link for ABS fault tracing - looks like 88 doesnt store codes which can be a problem. As for the 95, I'd get the codes pulled by someone with the equipement - cost my about £15 last time and it highlighted the exact problem.