C1234 on Ford

ABS wheel sensor output failure (Ford)

Severity: Inspect soon

The yellow ABS lamp means anti-lock may be off or acting falsely, so get the brakes checked soon.

It gets more serious if:

Safety-critical system: explanation only, no DIY steps. Source: how we rate severity

This page covers only what differs on Ford. For what C1234 means, the ranked causes and the test order, see the C1234 guide.

1998–2002 · Ranger
Supported by vehicle data
Ford bulletin 16021 covers C1233 and C1234 sensor output failures in slippery conditions on Explorer Sport, Sport Trac and Ranger. Whether the bulletin is still current is not verified.
2000 · Focus
Supported by vehicle data
Ford bulletin 8137 lists C1234 with a yellow 4WABS lamp or false ABS activation on the 2000 Focus. Whether the bulletin is still current is not verified.
2004 · Ranger
Supported by vehicle data
Ford bulletin 17132 says C1233 and C1234 are reversed in the Ranger ABS module, so the code can name the wrong wheel. Whether the bulletin is still current is not verified.
2002 · Explorer
Supported by vehicle data
Ford bulletin 16437 prescribes replacing the anti-lock brake electronic control unit for C1233 and C1234. Whether the bulletin is still current is not verified.

8137Status unverified
Yellow 4WABS lamp with wheel sensor codes
2000focus · NHTSA 612326
Lists C1234 with other wheel sensor codes or false ABS activation.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
16021Status unverified
4WABS codes C1233 and C1234 in slippery conditions
1998–2002explorer, ranger · NHTSA 636212
Calls them anti-lock brake sensor output failures.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
17132Status unverified
ABS C1233 and C1234 reversed in ABS module
2004ranger · NHTSA 10004049
Says the two codes are reversed in the ABS module.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
16437Status unverified
C1233 and C1234, replace ABS EUC
2002explorer · NHTSA 10008359
Summary says to replace the anti-lock brake electronic control unit.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
15813Status unverified
4WABS codes C1233 and C1234, sensor output failure
2001–2002ranger, explorer-sport-trac · NHTSA 637542
Calls the codes anti-lock brake sensor output failures.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Ford 16021: 4WABS codes C1233 and C1234 (anti-lock brake sensor output failures) in slippery conditions — Ford Motor Company via NHTSA
Ford 00-8-13: Yellow 4WABS lamp with C1145, C1234, C1233, C1265, C1235, C1175, C1236 — Ford Motor Company via NHTSA
Ford 17132: ABS DTC C1233 and C1234 reversed in ABS module — Ford Motor Company via NHTSA
Ford 16437: DTC C1233 and C1234, replace ABS EUC — Ford Motor Company via NHTSA

This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error