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Test 3 - Wheel Speed Sensor Signal Problem

NOTE: DTC 29 may set when vehicle is towed, raised or steering wheel is held at full lock continuously.
  1. Ensure tires are proper specification, pressure is correct and tires are not excessively worn. Repair or replace as needed.
  2. Ensure sensor bolts are tight. Ensure tone wheel bolts are tight. Tighten as needed. Go to next step.
  3. Check sensor to tone wheel air gap around entire wheel. Gap should be .035-.055" (.9-1.1 mm) front and .028-.047" (.7-1.2 mm) rear. If gap is too small, use Spacer (26755AA000) to increase gap to specification. If gap exceeds specification, remove spacer(s) or replace tone wheel or faulty wheel speed sensor. When gap is set, go to next step.
  4. If an oscilloscope is not available, go to next step. If an oscilloscope is available, raise and support vehicle with wheels off of ground. Turn ignition off. Disconnect ABS control module connector, remove cover and reinstall connector. Turn ignition on. Backprobe ABS control unit connector with oscilloscope test probes while rotating each wheel depending on trouble code. See Figure. See WHEEL SENSOR INPUT VOLTAGE table. Voltage should be .12-1.00 volt (AC waveform). If input voltage is not as specified or waveform is erratic, go to next step. If input voltage and waveform is as specified, go to step 6). This test procedure may set DTC 29.
    CHECKING WHEEL SENSOR INPUT VOLTAGE

    DTC (1) Terminals No.
    22 14 & 15
    24 49 & 19
    26 18 & 46
    28 16 & 17
    (1) Second terminal listed is to be connected to oscilloscope ground lead.
  5. Check sensor and tone wheel for damage or contamination. Clean, repair or replace as needed. Go to next step.
  6. Check hub runout. If runout is less than .002" (.05 mm), go to next step. If runout is .002" (.05 mm) or more, replace hub.
  7. Turn ignition off. Reconnect all connectors. Erase memory. Recheck trouble codes. If same trouble code returns, replace ABS control unit. If other trouble codes exist, go to proper test procedure. If no trouble codes exist, problem was a temporary poor contact. Check harness and connectors.
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