964 carrera 4 transmission diff erentiallock
Discussion
Not had my car very long but the couple of times I've used it today when I start up the warning light's on for the diff lock and ABS off. Once I go over 20ish mph this disengages as it should but how do I stop it from starting off in this mode in the first place?
I've tried turning the switch both ways but it doesn't seem to help - which way should I turn it and how long should I hold it for?
And with it being an import the handbook's in German...
I've tried turning the switch both ways but it doesn't seem to help - which way should I turn it and how long should I hold it for?
And with it being an import the handbook's in German...
Seems it can be a common fault and dont think its your diff lock (dont think you would make it to 20mph with it on!! bloody horrible noise at 5 mph):
Article from a newsletter below and link to the news letter - www.promax.eclipse.co.uk/pmnl200609.pdf
One of the common 'faults' with the 4 wheel drive 964 is triggering of the 4WD/ABS
warning lights for no apparent reason. The sequence is well known to anyone who
has had the problem. The 4WD drive and ABS lights go on together, the buzzer then
goes on to say it is a category 1 alarm, and the warning light comes on to say a
warning has triggered - all this in
under 1 second - and very
disconcerting if at speed. This article
presents a view on all current
probable causes (this is not inclusive
and other causes may have been
determined by others). Here is a
brief and simplified guide to this
problem:-
1. Poor earth connections leading to
insufficient current in the circuit.
Look for corrosion and check for
current draw. Clean all earth points.
2. Faulty spark plug boots causing high voltage spikes to earth that trigger the
alarm. Look for visible cracking, and/or incorrectly fitted boots. Make sure all boots
and insulation are correctly fitted and operational. Change if need be.
3. Cracks in the twin distributor unit
causing voltage spikes to earth that
trigger the alarm. Difficult to see hairline
cracks - needs proper checking. Make
sure the caps are not cracked, change if
need be. Look for hairline cracks and
moisture in the caps.
4. Water ingress on the electrical parts,
especially in the front boot area where
the pump etc is. Any water can lead to
circuit shorting. Make sure all
connections, etc, are dry and that no
moisture is present. Refix seals, etc as
needed. WD40 can sometimes help.
5. ABS brake pressure switch (on the pump unit) is leaking pressure, and/or other
pressure leaks in the system. Usually visible and/or takes a long time (3-4 seconds)
for the warning lights to go out when starting. Re-tighten connections (take care). If
needed change switch/unit. Approx £700 with labour.
6. Faulty sensors on the wheels (either faulty sensors, or sensors with dirty
contacts). The Bosch hammer may pick up a "missing ABS" or similar result. Clean all
contacts. If the sensors are at fault then they will need to be changed (on early cars
this will mean getting a new set (4 off) fitted since the sensors were upgraded over
the life of the 964. Approx £500 with labour.
7. Incorrect or faulty relay. Fit new relay (it is marked in the fuse box).
8. Tyres of the wrong radius fitted. This messes that 4WD logic for wheel spin
causing the alarm to trigger. Fit correct tyres. If you have after market wheels with
different tyre sizes, just be sure that the rolling radius is close to the original factory
specification (this also affects the speedometer reading too).
The two most likely causes are: leaking abs pump/switch, and poor earth
connections.
Article from a newsletter below and link to the news letter - www.promax.eclipse.co.uk/pmnl200609.pdf
One of the common 'faults' with the 4 wheel drive 964 is triggering of the 4WD/ABS
warning lights for no apparent reason. The sequence is well known to anyone who
has had the problem. The 4WD drive and ABS lights go on together, the buzzer then
goes on to say it is a category 1 alarm, and the warning light comes on to say a
warning has triggered - all this in
under 1 second - and very
disconcerting if at speed. This article
presents a view on all current
probable causes (this is not inclusive
and other causes may have been
determined by others). Here is a
brief and simplified guide to this
problem:-
1. Poor earth connections leading to
insufficient current in the circuit.
Look for corrosion and check for
current draw. Clean all earth points.
2. Faulty spark plug boots causing high voltage spikes to earth that trigger the
alarm. Look for visible cracking, and/or incorrectly fitted boots. Make sure all boots
and insulation are correctly fitted and operational. Change if need be.
3. Cracks in the twin distributor unit
causing voltage spikes to earth that
trigger the alarm. Difficult to see hairline
cracks - needs proper checking. Make
sure the caps are not cracked, change if
need be. Look for hairline cracks and
moisture in the caps.
4. Water ingress on the electrical parts,
especially in the front boot area where
the pump etc is. Any water can lead to
circuit shorting. Make sure all
connections, etc, are dry and that no
moisture is present. Refix seals, etc as
needed. WD40 can sometimes help.
5. ABS brake pressure switch (on the pump unit) is leaking pressure, and/or other
pressure leaks in the system. Usually visible and/or takes a long time (3-4 seconds)
for the warning lights to go out when starting. Re-tighten connections (take care). If
needed change switch/unit. Approx £700 with labour.
6. Faulty sensors on the wheels (either faulty sensors, or sensors with dirty
contacts). The Bosch hammer may pick up a "missing ABS" or similar result. Clean all
contacts. If the sensors are at fault then they will need to be changed (on early cars
this will mean getting a new set (4 off) fitted since the sensors were upgraded over
the life of the 964. Approx £500 with labour.
7. Incorrect or faulty relay. Fit new relay (it is marked in the fuse box).
8. Tyres of the wrong radius fitted. This messes that 4WD logic for wheel spin
causing the alarm to trigger. Fit correct tyres. If you have after market wheels with
different tyre sizes, just be sure that the rolling radius is close to the original factory
specification (this also affects the speedometer reading too).
The two most likely causes are: leaking abs pump/switch, and poor earth
connections.
I wouldn't worry to much about this.
I've had my car for nearly three years and ever since I've had it the lights take a while to go out.
This usually takes longer the longer the car has been standing. After the car has been used for a few consecutive journeys it goes out straight after starting. If it's been standing for a few weeks the can take a couple of minutes to go out.
Like the previous post says, electrical/wager ingress on the abs/pdas controller (front left of front bonnet, think it has a Bosch label on) has caused people on other forums some agro, but a quick check of the connection should say whether you have this issue or not. Look for dis-coloured pins.
I think it has something to do with pressure in the hyd. system building up to a required level.
Do you get the buzzer alarm or just the lights?
Rob
I've had my car for nearly three years and ever since I've had it the lights take a while to go out.
This usually takes longer the longer the car has been standing. After the car has been used for a few consecutive journeys it goes out straight after starting. If it's been standing for a few weeks the can take a couple of minutes to go out.
Like the previous post says, electrical/wager ingress on the abs/pdas controller (front left of front bonnet, think it has a Bosch label on) has caused people on other forums some agro, but a quick check of the connection should say whether you have this issue or not. Look for dis-coloured pins.
I think it has something to do with pressure in the hyd. system building up to a required level.
Do you get the buzzer alarm or just the lights?
Rob
iamthestig said:
No warning buzzer but it does feel like the diffs are locked as the turning circle becomes even bigger and the car is difficult to manoeuvre. Which way does one turn the switch do unlock them anyway?
Top of my head I'm not sure, if someone doesn't post I'll have a look tomorrow and let you know.
Never heard of the diffs. locking without you turning the knob so can't help.
Have you tried a search on Rennlist?
Rob
Hi Richard
This seems to be one of the most common, and frustrating faults on the 964 - happens quite regularly on mine and particularly in the wet (so, if it's anything like it is here in Bristol at the moment, that means quite a lot). There are plenty of posts on Rennlist...Check out the following post http://forums.rennlist.com/rennforums which is on the same subject.
In the meantime... (and 'cos you're German ain't up to much
)
From the manual:
The right "Traction Program" switch completely locks the longitudinal and transverse differential, when the vehicle is stopped and at speeds of up to approx 30 km/h. Full inetrlocking is automatically released above 40 km/h.
The traction program must not be activated if the wheels are slipping.
This function is designed to get the vehicle moving, and is not suitable for normal road driving. The increased differntial lock causes strain and noise, especially in tight curves or while manoeuvring. It also results in sever understeer.
If the ABS takes effect while the traction program is on, full differential locking is automatically disabled.
Traction program on - Switch to the right; indicator light on switch blinks
Traction program off - Switch to the left; indicator light off
It would be worth getting hold of Adrian Streather's book (if you don't have it already) - Porsche 911 Enthusiast's Companion (ISBN 0-8376-0293-9) Bit pricey but worth it!
Hope it helps
This seems to be one of the most common, and frustrating faults on the 964 - happens quite regularly on mine and particularly in the wet (so, if it's anything like it is here in Bristol at the moment, that means quite a lot). There are plenty of posts on Rennlist...Check out the following post http://forums.rennlist.com/rennforums which is on the same subject.
In the meantime... (and 'cos you're German ain't up to much
) From the manual:
The right "Traction Program" switch completely locks the longitudinal and transverse differential, when the vehicle is stopped and at speeds of up to approx 30 km/h. Full inetrlocking is automatically released above 40 km/h.
The traction program must not be activated if the wheels are slipping.
This function is designed to get the vehicle moving, and is not suitable for normal road driving. The increased differntial lock causes strain and noise, especially in tight curves or while manoeuvring. It also results in sever understeer.
If the ABS takes effect while the traction program is on, full differential locking is automatically disabled.
Traction program on - Switch to the right; indicator light on switch blinks
Traction program off - Switch to the left; indicator light off
It would be worth getting hold of Adrian Streather's book (if you don't have it already) - Porsche 911 Enthusiast's Companion (ISBN 0-8376-0293-9) Bit pricey but worth it!
Hope it helps
epoch911 - you're a true gent thanks for your help.
When I started the car this morning the warning lights were on for the diff lock and ABS but I just held the switch to the left for about 8-10 seconds and they went out. Hopefully now that means that the car knows I don't want the diffs locked on start-up and won't do it anymore.
When I started the car this morning the warning lights were on for the diff lock and ABS but I just held the switch to the left for about 8-10 seconds and they went out. Hopefully now that means that the car knows I don't want the diffs locked on start-up and won't do it anymore.
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