The front brakes locked with multiple ABS codes?

2013 HYUNDAI ELANTRA
128,648 MILES
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CHRISPD
  • MEMBER
  • 2 POSTS
Hello,

The front brakes locked up on my vehicle listed above and after a scan I have 4 codes and the ABS light is on.
C1237 Primary pressure sensor signal
C1687 CAN time out
C1623 CAN time out steering angle
C1513 Brake switch error (I did replace a broken brake switch pad on the brake pedal)
Not sure where to start and would greatly appreciate any help.
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Jul 17, 2024 at 4:57 PM
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BORIS K
  • CERTIFIED EXPERT
  • 836 POSTS
Hello,

The main code to work with is C1237.

The failure is detected if the pressure sensor signal is out of normal range, or the pressure sensor signal is changed abnormally. In spite of no brake switch signal, master cylinder pressure exceeds 20bar when brake switch is normal. Meaning that the ABS control module is seeing a higher-than-normal pressure without the brakes being applied.

The pressure sensor, installed in the HECU, senses the brake pressure to judge a driver's brake intention when the ESP program is operated. If pressure of master cylinder is applied to pressure sensor, the strain of the piezo element is changed and then the resistance of bridge circuit is changed according to the changed strain. Therefore, this changed resistance changes the output voltage of bridge circuit and the output voltage changes linearly. The sensor output is an analogue signal in proportion to the supply voltage, and the HECU recognizes a pressure value according to signal ratio about supply voltage.

As the description indicates the pressure sensor is internal of the HECU (Hydraulic Electronic Control Unit), ABS, and is not repairable.

Cheers, Boris

Jul 18, 2024 at 1:41 AM