92 964 tip:ABS light, speedo out, tip manual out, spoiler light

[911Obbie]

So - have owned this 92 targa tip since 2000. Rebuilt the engine 6 yrs ago.

This happened 3 weeks ago:
ABS light came on
Speedometer quit working
Tip on the manual side switches back to automatic after 2 minutes, and
Spoiler only works manually.

I also have the Durametric software for this car.
TIP ECU had not faults.
Motronic ECU 1 minor fault (it has never like my chip upgrade since 2003).
Most of the faults were AC/heater flaps issues.

Jumped on the forums here and Rennlist.
Cleaned front left sensor and replaced ABS relay with hew one from our host.
Everything above still the same.

I know the ABS unit has relays that may be suspect.
The car runs very powerfully since the rebuild, but this is annoying.

Any thoughts on what do to do next?
Thanks for any help!

[ian c2]

Abs supplies speedo , speedo supplies spoiler .
So concentrate on abs system .
Start with sensors , and power .

[911Obbie]

Thanks. Good summary of much of what I've been reading.
Will advise of progress and solutions for benefit of the forum.

[group911@aol.co]

Correct. If I remember right, the left front sensor is where it's read from.

Originally Posted by ian c2

Abs supplies speedo , speedo supplies spoiler .
So concentrate on abs system .
Start with sensors , and power .

[911Obbie]

Thanks.
Starting the process to work backwards from ABS sensors and connectors. Likely have to have codes checked re relays and FCU if sensor signals and signal paths are good.

[power_up]

Originally Posted by 911Obbie

So - have owned this 92 targa tip since 2000. Rebuilt the engine 6 yrs ago.

This happened 3 weeks ago:
ABS light came on
Speedometer quit working
Tip on the manual side switches back to automatic after 2 minutes, and
Spoiler only works manually.

I also have the Durametric software for this car.
TIP ECU had not faults.
Motronic ECU 1 minor fault (it has never like my chip upgrade since 2003).
Most of the faults were AC/heater flaps issues.

Jumped on the forums here and Rennlist.
Cleaned front left sensor and replaced ABS relay with hew one from our host.
Everything above still the same.

I know the ABS unit has relays that may be suspect.
The car runs very powerfully since the rebuild, but this is annoying.

Any thoughts on what do to do next?
Thanks for any help!

I have the similar problem occasionally. ABS light up and buzzer sound, Speedo meter quit working. Finding what to look up first. Hope you have clue.

[911Obbie]

I was very methodical wth the engine rebuild. Same approach here.
Was hoping the ABS relay change out would be the simple fix.
Will test ABS signal paths first.
Then power.
Then get codes read ie FCU and ABS unit relays.
If all is good then I've got to look at speedo.
Will keep all updated.

[bazar01]

Originally Posted by 911Obbie

I was very methodical wth the engine rebuild. Same approach here.
Was hoping the ABS relay change out would be the simple fix.
Will test ABS signal paths first.
Then power.
Then get codes read ie FCU and ABS unit relays.
If all is good then I've got to look at speedo.
Will keep all updated.

- Speedometer pin4 goes to R24 pin5 (FCU for control unit)
- R24 pin6 (input signal) goes to Wiring Diagram grid C35
- Grid C35 refers to ABS control unit pin17. (FRONT LEFT)

[power_up]

Originally Posted by power_up

I have the similar problem occasionally. ABS light up and buzzer sound, Speedo meter quit working. Finding what to look up first. Hope you have clue.

Updated my situation: My problem solved by replacing the R34 relay.

[911Obbie]

UPdate-
No signal from the left front sensor with a DVM.
Then did a brake test - 60 MPH, hits brakes hard..... front left wheel locked up.
Will procedd from here.
Thx for inout.

[group911@aol.co]

That sensor is easy to pull and inspect. It could be as simple as a bunch of metal fragments attached since it's magnetic.

Originally Posted by 911Obbie

UPdate-
No signal from the left front sensor with a DVM.
Then did a brake test - 60 MPH, hits brakes hard..... front left wheel locked up.
Will procedd from here.
Thx for inout.

[911Obbie]

I pulled, cleaned and reinstalled the sensor few weeks ago. It was pretty BAD. I didn't check the output at that time. Have ordered one from our host.

[group911@aol.co]

I think you can also swap left to right to quickly assess the issue

[911Obbie]

Thanks Bob.
Will keep working my way up the signal chain.
Do you know if this left front sensor feeds the entire signal path - ABS, frequency counter, speedo, tip ECU and spoiler? and, does the FCU have a code if in fact it's the culprit?
What's odd when I had it out was the Tip worked for 2 minutes then stopped. Speedo did not, spoiler did not and ABS remained lit the whole time. 120 second each on/off . ??

[group911@aol.co]

I don't know if it feeds all that but I'll bet Ian knows.

[ian c2]

It’s easy enough to check all 4 wheel sensors with a meter .
Unplug and insert test leads , and read ohms .
Should be around 1k , then spin hub slowly to see the reading move .
Another way is with a continuity beeper , should beep when plugged in but go on/off when hub rotated slowly .
Bear in mind pad sensor is simply open/closed so make sure you are connected into the right plug !!!





I will clear space , and pm you my email as will be easier .

[ian c2]

Originally Posted by 911Obbie

Thanks Bob.
Will keep working my way up the signal chain.
Do you know if this left front sensor feeds the entire signal path - ABS, frequency counter, speedo, tip ECU and spoiler? and, does the FCU have a code if in fact it's the culprit?
What's odd when I had it out was the Tip worked for 2 minutes then stopped. Speedo did not, spoiler did not and ABS remained lit the whole time. 120 second each on/off . ??

Wheel sensor goes to abs , abs goes to converter then speedo , speedo goes to spoiler .
When you say tip worked then stopped , you mean worked in manual then stopped ?
Did it fall into 3rd gear ? (Limp home mode)

Simple things first , is your battery good and fully charged ?
It’s pretty much a must for troubleshooting on any “modern” car …
Did you do a hard reset by disconnecting battery for 20mins +

[911Obbie]

Pic looks familiar with the leads in the ABS connector..... nothing. Waiting for the new one from
our host.

Re Tip not working: I can shift through 4 gears Tip mode, then after 2 minutes, the Tip gear indicator light on speedo goes out and drops to 4th. Not limp home mode but fully automatic. And runs great in that mode. First time i thought it was limp home mode (wasn't), pulled over. turned off, waited couple minutes, started back up and went through all 4 in Tip mode then back to only auto mode after couple minutes. Quite puzzling.

New battery last year. Holds strong charge ( I keep a bat/alt monitor that plugs in to cig lighter for occasional check . Replaced alternator 2 years ago.).

I have a battery disconnect because I sometimes don't drive for a couple months (but garage kept and does not see rain; it's also in most of the winter). So, yes it gets a hard reset regularly.

Appreciate any thoughts and help as I start working up the signal chain.

[ian c2]

If you definately have a sensor that tested bad , let’s wait to replace that before we work up the signal chain .
The front 2 sensors are the same , should you wish to swap whilst waiting for a replacement .

Another quick check while you have a repeatable fault , if you can please try to pull over and starting in neutral after a tip fault .

The good news is , you have a repeatable fault !!
Much easier to troubleshoot than an intermittent fault …

Next step would probobly be the speedo converter , as that takes a wheel speed sensor and converts to speedo signal . Speedo then controls spoiler through spoiler control unit .
If the converter is bad you lose speedo , and everything it controls .
You should find the speed signal converter in the front fuse box iirc

[group911@aol.co]

Ian
What does the neutral start tell you?

Originally Posted by ian c2

If you definately have a sensor that tested bad , let’s wait to replace that before we work up the signal chain .
The front 2 sensors are the same , should you wish to swap whilst waiting for a replacement .

Another quick check while you have a repeatable fault , if you can please try to pull over and starting in neutral after a tip fault .

The good news is , you have a repeatable fault !!
Much easier to troubleshoot than an intermittent fault …

Next step would probobly be the speedo converter , as that takes a wheel speed sensor and converts to speedo signal . Speedo then controls spoiler through spoiler control unit .
If the converter is bad you lose speedo , and everything it controls .
You should find the speed signal converter in the front fuse box iirc