Code 29

Inspect size and condition of tires. Ensure tire is correct size. See tire placard under driver's door latch. If individual tire is unevenly worn compared to other tires on vehicle, trouble code may be set. Replace tire(s) as needed.
Ensure ignition is off. Raise and support vehicle. Ensure ABS control unit harness connector is disconnected. See Figure . Remove harness connector back cover. Connect harness connector to ABS control unit. Turn ignition on. Using oscilloscope, check wheel sensors voltage input (waveform).
NOTE: After completing inspection of sensors clear memory of control unit. Code 29 may be stored due to test.

Backprobe control unit connector with oscilloscope test probes. See Figure . Rotate each wheel depending on trouble code. Connect probes to selected terminals. See WHEEL SENSOR INPUT VOLTAGE table. Voltage should be .12-1.0 volts (A/C waveform). If input voltage is not within specification or waveform is erratic, go to next step. If input is within specification, replace ABS control unit.

WHEEL SENSOR INPUT VOLTAGE

Trouble Code

⁽¹⁾ Terminals

21 & 23

23 (4WD)

4 & 22

23 (FWD)

4 & 5

24 & 26

8 & 9

⁽¹⁾	Using voltmeter, measure voltage between specified terminals.

Check resistance of wheel sensors. Disconnect wheel sensor harness connector. Using ohmmeter, check resistance between sensor connector terminals. Resistance should be .8-1.3 ohms. If resistance is not within specification, replace wheel sensor. If sensor resistance is within specification, inspect sensor air gap. Go to next step.
Inspect wheel speed sensor air gap. See WHEEL SPEED SENSOR AIR GAP under ADJUSTMENTS. Adjust as necessary. Ensure sensor(s) are not damaged. If sensor adjustment is within specifications and no damage is present, replace wheel sensor.