[sigis]

Hi,

my name is Sigitas, I'm from Lithuania. I'm still new here

Hope to find usefull info here

So , some weeks ago the problem with ABS appeared at with my vehicle. Sometimes ABS activates , when is no need for it. Especially at the low speed (while parking for example). And ABS is triggering my brake pedal almost every time I hit it. ABS or TC indicator doesn't light on. There are no errors on a panel. Today we checked the voltage on ABS sensor with LAUNCH. Three sensors has approx 2,3-2,4V on. Rear right has only 1,54V. Then we disconnected all the sensors. Three sensors had 0V. Except this one rear-right - it anyway had 1,54V. Resistance of all sensors are approx 980-1000 ohms. So the sensors seem to be good. The we replaced the ABS ECU - no changes. This "vibro" break pedal is getting me off. Where could we look for a problem now? Thank You for Your answers.

P.S. My RR P38 is 99->

 

[300AJC]

Similar happened with my TD5 Discovery. It could be a faulty ABS sensor or you may need a new hub.

Oh, and.......:welcome2:

 

[sigis]

ABS Sensors seem to be OK, tried to replace each one. The problem is progressing every day, when it started - it was approx 1 time of 5 pedal hits. Now ABS triggering almost everytime.

 

[300AJC]

Mine was still under warranty. The garage assumed it needed a new hub and replaced two. It turned out to be a wring fault near the ECU. A new hub might be the consensus of opinion though.

 

[sigis]

in D2 hub goes with bearing and ABS sensor as a kit. RR P38 hub bearing can be replaced independently. I didn't any "broken bearing" sound while driving

 

[wammers]

All sensors should read the same. If one is reading differently to the others the the ABS ECU thinks that wheel is skidding and operates ABS. Simples.

 

[sigis]

even disconnected sensors showing different voltages via "LAUNCH". ECU of ABS was replaced also, results and voltages left the same.

 

[Datatek]

even disconnected sensors showing different voltages via "LAUNCH". ECU of ABS was replaced also, results and voltages left the same.

Check the wiring back to the ECU, corroded connectors, bad earths may be the cause. Check routing of the wires with RAVE.

 

[sigis]

please say where these wirings go through ? place under the passengers (LHD) footplace sometimes go wet, but the wires seem to be ok, dried them last summer

 

[The Mad Hat Man]

my sons car had the same prob. it was a broken abs ring. every time the brakes were pressed the same wheel gave a "locked" reading and ABS was activated.

 

[300AJC]

Check the wiring back to the ECU, corroded connectors, bad earths may be the cause. Check routing of the wires with RAVE.

That turned out to be the problem with my Discovery in the end.

 

[Datatek]

my sons car had the same prob. it was a broken abs ring. every time the brakes were pressed the same wheel gave a "locked" reading and ABS was activated.

But he has an erroneous voltage on the wires from the ECU Mad

 

[Datatek]

please say where these wirings go through ? place under the passengers (LHD) footplace sometimes go wet, but the wires seem to be ok, dried them last summer

There are 2 connectors behind the kick panel in front of the door, not sure but one of those might be involved. RAVE would confirm. They are well known for corrosion and one affects the EAS, not sure about the other.

 

[The Mad Hat Man]

But he has an erroneous voltage on the wires from the ECU Mad

Yeah. I didn't say that was the problem - just another option.

I wasn't sure if it was an erroneous voltage or just a steady state voltage, which, of course a broken/ missing reluctor ring could give.

 

[Datatek]

Yeah. I didn't say that was the problem - just another option.

I wasn't sure if it was an erroneous voltage or just a steady state voltage, which, of course a broken/ missing reluctor ring could give.

The voltage is there according to the OP with the sensor disconnected.

 

[wammers]

Yeah. I didn't say that was the problem - just another option.

I wasn't sure if it was an erroneous voltage or just a steady state voltage, which, of course a broken/ missing reluctor ring could give.

The voltages to ALL the sensors MUST be the same before a reluctor ring comes into play. If the voltage to one sensor is wrong to start with, the ECU will always think that wheel is locking and apply ABS when brake is applied.

 

[The Mad Hat Man]

The voltage is there according to the OP with the sensor disconnected.

I would expect that - as the sensor doesnt supply a voltage. the ABS ECU supplies a steady voltage and the sensor is triggered by the reluctor ring to chop the voltage into a square wave, frequency dependant on rotational speed. If the voltage from the ECU is different for one sensor to the others, does that not imply a dodgy ECU? But having said that, I wasnt disagreeing with you - just stating another reason why an ABS system could continiously trigger.

is the rangie a 3 wire system? Magnetic or hall effect?

 

[sigis]

There are 2 connectors behind the kick panel in front of the door, not sure but one of those might be involved. RAVE would confirm. They are well known for corrosion and one affects the EAS, not sure about the other.

can't find about what connectors You're talking about ... Could You post any screenshots...

About the voltages:

voltages are the same when problem started and now.. But ABS triggers more often.. Even every time I kick the brake pedal , at the speed lower than 40km/h

 

[sigis]

no ABS errors on the panel. I think if there was a trouble with sensors - it would be displayed on the panel.