Circuit Description
The speed sensor used on this vehicle is a multiple pole magnetic pickup. This sensor produces an AC signal that the EBCM/EBTCM uses the frequency from to calculate the wheel speed.
Conditions for Setting the DTC
The DTC can be set when the brake is off and no wheel speed DTCs (DTC C1232 through C1235) are present.
This DTC will set anytime the EBCM sees a wheel speed variation of more than 24 Km/h (15 mph) in 0.01 seconds. The 14 Km/h (15 mph) change must occur 5 times with less than 1.00 seconds between each occurrence for a code to be set.
Action Taken When the DTC Sets
| • | A malfunction DTC stores. |
| • | The ABS/ETS/TCS disables. |
| • | The amber ABS/ETS/TCS indicator(s) turn on. |
Conditions for Clearing the DTC
| • | Condition for DTC is no longer present and scan tool clear DTC function is used. |
| • | 100 ignition cycles have passed with no DTC(s) detected. |
Diagnostic Aids
| • | It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction. |
| • | An intermittent malfunction can be caused by poor connections, broken insulation, or a wire that is broken inside the insulation. |
| • | If an intermittent malfunction exists refer to Intermittents and Poor Connections Diagnosis in Wiring Systems. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Diagnostic System Check performed? | -- | ||
2 | Did DTC C1234, C1291or C1293 set as a current or history code? | -- | Go to DTC C1234 LR Wheel Speed Circuit Open or Shorted DTC C1291 Open Brake Lamp Switch Contacts During Deceleration or DTC C1293 Code C1291 Set in Previous Ignition Cycle | |
3 |
Is physical damage of sensor evident? | -- | ||
4 | Replace wheel speed sensor. Refer to Wheel Speed Sensor Replacement . Is the repair complete? | -- | -- | |
5 | Inspect the WSS jumper harness for physical damage. Is physical damage to the jumper harness evident? | -- | ||
6 | Replace wheel speed sensor jumper harness. Refer to Wheel Speed Sensor Jumper Harness Replacement . Is the repair complete? | -- | -- | |
7 |
Is the resistance within the range specified in the value(s) column? | 850-1350 ohms | ||
8 |
Does the AC voltage fall below the specified value? | 100 mV | ||
9 |
Is there continuity between terminals A3 and A4 of the Universal Pinout Box? | -- | ||
10 | Repair the short between CKT(s) 884 and 885. (If a short is found in the jumper harness, replace the jumper harness assembly.) Is the repair complete? | -- | -- | |
11 |
Does DTC reset as a current DTC? | -- | System OK | |
12 | Replace EBCM/EBTCM. Refer to Electronic Brake Control Module/Electronic Brake and Track Control Module Replacement . Is the replacement complete? | -- | -- |
