Rick's Free Auto Repair Advice

ABS light on – C1145, C1234

Fix code C1145, C1234 ABS light on

If you own a 2003 Mercury Mountaineer 4.0L, FLEX, Vin K and have Anti-lock Brake System (ABS) light on and trouble codes C1145 or C1234, you may have a bad connection at the wheel speed sensor. Start by inspecting the Right Front (RF) wheel speed sensor connections for physical
damage. Look for a corroded connection or broken wire. If the sensor shows any signs of physical damage, check the wheel hub and tone ring. Replace the wheel hub or tone ring assembly as needed.

Next, disconnect the sensor connector and measure the voltage between the Yellow/Black (YE/BK) wire and the Yellow/Red (YE/RD) wire with the ignition switch in the RUN position. You should see voltage greater than 9.0 volts.

If the voltage is lower than that, check the individual circuits for a possible open circuit, short to ground, or short to each other. Do those checks before suspecting a bad ABS module.

If the voltage checks out. replace the sensor. Then clear the codes and drive the vehicle. Recheck to see if the codes set again.


© 2012 Rick Muscoplat

Posted on by Rick Muscoplat

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