ABS light is on codes C1226, C1233, and C1236?

2003 BUICK CENTURY

181,000 MILES • 3.1L • 6 CYL • 2WD • AUTOMATIC

JEFF HERMAN

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486 POSTS
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ABS light on, tested DC voltage at connector 4.85v with probes in one direction, 3.17v with probes in other direction. Stationary AC voltage on sensor .08v. When rotating hub I get .1 volts. Shouldn't stationary voltage be 0.0v? The sensor is part of the wheel hub so I can't look at tooth wheel or air gap. ABS codes are C1226, C1233, and C1236. Ohms across sensor was 2093.

Aug 18, 2022 at 7:42 AM

STRAILER

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The fact that three out of the four corners are having an issue with the sensor I would say the ABS controller has gone bad, the reading for the sensors look normal. Here is how to change out the controller to see if this fixed the problem. The only other thing is if the ABS light has been on for years the hub bearing could be boing out on the respective corner. Here is a video of the job being done in a similar vehicle:

https://youtu.be/lUotkKXG9dY

Check out the diagrams (below). Please let us know what happens.

Images (Click to enlarge)

Aug 18, 2022 at 11:59 AM

JEFF HERMAN

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486 POSTS

Only right front codes.

Aug 18, 2022 at 12:35 PM

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C1226 Code - Right Front Excessive Wheel Speed Variation
C1233 Code - Left Front Wheel Speed Sensor Input Signal
C1236 Code - Left Rear Wheel Speed Sensor Input Signal

Aug 19, 2022 at 11:04 AM

JEFF HERMAN

MEMBER
486 POSTS

Hmm, thought scanner said all R front. It's a stretch but could a broken coil spring trigger an ABS code?

Aug 19, 2022 at 7:30 PM

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CERTIFIED EXPERT
53,854 POSTS

Bad wiring can cause issues like this for sure.

Here is the ABS system wiring diagrams and a guide on how to check the connections:

https://www.2carpros.com/articles/how-to-check-wiring

Check out the diagrams (below). Please let us know what you find.

Images (Click to enlarge)

Aug 20, 2022 at 5:01 PM