ABS Module vs Sensor?

[roddyrich]

Hi all

I have a 2014 MK 7 Golf GTI. Over the last year or so, I've been getting a string of error codes - ACC, ESC, Start-Stop, Hill Hold assist, TPSM. These error codes disappear after killing the engine for 10-20 mins. I note that these fault codes are very intermittent and happen only every 2-3 months. They also always during driving, especially when turning, and these errors never pop up on ignition or start up.

A quick search suggested that this could be caused by a faulty ABS sensor. I've taken the car to two different mechanics, one suggests it is a faulty ABS module, the other suggests its a faulty ABS sensor as they said it's uncommon for the whole module to fail.. However, the issue is that because the faults are very intermittent, by the time I get the car to the mechanic, all of the fault codes have disappeared by the time they scan it. I've since bought myself a ODB11 and have managed to scan the car when all the faults came up - no mention of a faulty ABS sensor comes in the report, but it did show an error saying "Lost communication with ABS module" along with a bunch of intermittent non specific error codes ("databus error value", "internal malfunction" etc.)

I guess i feel uncertain because the general public concensus with this issue is that it is caused by a faulty ABS sensor, but at the same time it could very well be the ABS module. I was told that a faulty sensor would cause the issue to be constant rather than intermittent - is that true?

Any thoughts?

 

[bcastine1]

You have an electrical gremlin. So there is no codes stored when checked with obd eleven? first thing you need to figure out is if your issue in on the 5 volt or 12 volt circuit, if i remember correctly 5 volt will be stored as a sensor B reference error, 12volt sensor A. As an example, when my car had its bout with elec. gremlins it was the 5 volt circuit. threw a sensor B code and also throttle body codes. you would be driving, then sudddenly epc light, every error, the same you mention would illuminate, gas pedal would not communicate to the throttle body, car would shift to first gear, not move and the idle was erratic. Basically car stranded. One would assume the gas pedal or throttle body failed. Nope, ended up being the boost pressure sensor on the lower intercooler pipe lol. The maf sensor, boost pressure sensor, water pump elec. connector, ABS and throttle body all have a part in the 5 volt system, i'm likely omitting others, but anyone of them can make you think something else is failing. Inspect all connectors to these modules and sensors, mine had some light corrosion between two pins, likely coming from the inside of the sensor. this sensor sits real low and is only protected by the plastic skid plate so it kinda makes sense it could fail . Another common spot for this to fail is the water pump connector, especially if your water pump is leaking, this pretty much requires you to remove the intake manifold to check however.