DTC 21 Right Front Wheel Speed Sensor Fault

Toothed wheel generates a voltage pulse as it moves past sensor. EBTCM/EBCM uses these pulses to determine wheel speed. EBTCM/EBCM uses wheel speed sensor signal to calculate vehicle reference speeds and speed, acceleration and slip values for each wheel. These values are used to determine when anti-lock control is needed.

EBTCM/EBCM will only set one wheel speed sensor DTC at a time, even if multiple faults exist. Detection is prioritized accordingly: LF, RR, LR and RF. Check for additional stored DTCs after making repairs.

DTC 21 will set if there is a short to ground or battery voltage in circuits No. 872 or 833, or a faulty wheel speed sensor. DTC 21 may set if circuits No. 872 or 833 lose continuity and wheel speed sensor signal is lost while driving. DTC 23 should accompany this DTC on next ignition cycle. If DTCs 21 and 23 are set concurrently, diagnose DTC 23 first.

1. Checks if DTC resets during a road test.
2. Use Tech 1 to check for sources of induced electrical noise.
3. Checks for damaged wheel speed sensor circuit shield.
4. Checks for intermittent opens/shorts in wheel speed sensor circuits and cables.
5. Checks for correct resistance in sensor.
6. Checks for a short to battery voltage in either speed sensor circuit wires.
7. Checks for a short between speed sensor circuit wires.
8. Checks for short to ground in speed sensor input circuit wire. A short with a resistance less than 2 megohms, though not a hard short, can still cause DTC 21 to set.
9. Checks wiring and connections for intermittents.