Range Rover L322 ABS

Niall Owner/Technician Stirling, United Kingdom Posted   Latest  
Question
Braking
Left Rear Sensor Code For Open Circuit

Posting vehicle details here can't get them to stay in the Vehicle Box 2003 RHD Range Rover L322 SALLMAMA33A133796

Customer has this vehicle back at the moment. History of problem, needed complete rear subframe replaced, new Pagid rear ABS sensors fitted, all good at first. Now we have an intermittent fault (I did approx 100 mls with no problems) with the left rear sensor which also kills the speedo, according to service info these are 2 wire hall effect sensors which are supplied with 8 volts (stabilized?) providing a signal voltage of between 0.75 and 2.5 volts. To check continuity from the ABS ECU to the rear sensors I did a diode test results were 0.5v one way and 0.89v connected the other way, the right rear had exactly the same readings. So what about the original front sensors tested the same way results nothing open circuit???. I have also tested both rear and one front for this 8 volt supply (sensors disconnected) no voltage reading bar a few mv. I have also noticed that when my Launch is connected to read the wheel speeds the fault will trip much faster, it can also trip without moving. Hope this makes some sense.

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Rick Technical Support Specialist
Saint Charles, Missouri
Rick Default
 

My guess is clear codes and back probe connected sensors for 8v feed and toggle voltage of .75 - 2.5v.

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Niall Owner/Technician
Stirling, United Kingdom
Niall Default
 

Hi Rick I had made up a breakout cable which I tried on one of the front sensors still lacking the 8 volt supply (the system is working with no codes)

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Stuart Owner/Technician
Prestonpans, United Kingdom
Stuart Default
 

Personally I always load test wires with a halogen bulb, Resistance test is futile!! and proves a single strand if wire exists in the circuit. Can the sensors be swopped side to side to see if fault moves. Hope this helps.

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Niall Owner/Technician
Stirling, United Kingdom
Niall Default
 

Hi Stuart definitely the right way to load the wiring, in this case I had the sensors connected and knowing that they are very sensitive is why I used the diode test on the DVOM just puzzled why the readings were different front to back.

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Allen Owner/Technician
Dallas, Texas
Allen Default
   

Seen it multiple times. Figure you checked the connector to the module for corrosion "melted" pins; really typical issue. If they are good; my bet would be the module is bad. Replaced 5+ for this issue. If all the pins are good iirc bba can fix them. ALSO MODULS JUST SWAP IN; SO USED ONES ARE A GO. allen

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Niall Owner/Technician
Stirling, United Kingdom
Niall Default
 

Hi Allen all looks good at the connector, I would really like to know if anyone while testing these gets the 8 volt supply, also what result would come from a genuine Land Rover sensor on the rear. (I have seen warnings about even testing with a DVOM on ohms)

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Allen Owner/Technician
Dallas, Texas
Allen Default
 

Honestly sir; have not pinpoint tested. First one many years ago got code and looked at data...replaced sensor. Same code; load tested continuity, was good, swapped in test module; fixed. Sold module. common enough that when we get those codes, we look at wheel hub; then throw in test module...boom. according to topix(attached) appears typical hall effect voltage. Have probed abs on multiple…

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Niall Owner/Technician
Stirling, United Kingdom
Niall Update
 

Hi All customer has sold this Range Rover so I might not see it again, I do have an other coming in so will do some checks with that one. A different post (ECU shutting power off when in fault condition) re these sensors might lead me to believe that as Rick said back-probe with sensors connected and faults cleared.

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