Circuit Description
The wheel speed sensor coil emits an electromagnetic field. A toothed ring on the wheel passes by the wheel speed sensor and disrupts this electromagnetic field. The disruption in the field causes the wheel speed sensor to produce a sinusoidal (AC) voltage signal. The frequency and amplitude of the sinusoidal (AC) voltage signal are proportional to the speed of the wheel. The amplitude of the wheel speed signal is also directly related to the distance between the wheel speed sensor coil and the toothed ring. This distance is referred to as the air gap.
Conditions for Setting the DTC
| • | No output signal from the right front wheel speed sensor for 1.0 second |
| • | Excessive right front wheel speed sensor resistance for 1.0 second |
Action Taken When the DTC Sets
| • | The ABS indicator lamp turns on |
| • | The ABS disables |
DTC C0221 is a Condition Latched DTC, which indicates that the above actions remain true only as long as the condition persists.
Conditions for Clearing the DTC
| • | Repair the conditions responsible for setting the DTC |
| • | Use the Scan Tool Clear DTCs function |
Diagnostic Aids
Any of the following conditions may cause an intermittent malfunction:
| • | A poor connection |
| • | Wire insulation that is rubbed through |
| • | A wire breaks inside the insulation |
Thoroughly check any circuitry that is suspected of causing the intermittent complaint for the following conditions:
| • | Backed out terminals |
| • | Improper mating |
| • | Broken locks |
| • | Improperly formed or damaged terminals |
| • | Poor terminal to wiring connections |
| • | Physical damage to the wiring harness |
When inspecting a wheel speed sensor, inspect the sensor terminals and the harness connector for corrosion. If evidence of corrosion exists, then replace the wheel speed sensor. Refer to Wheel Speed Sensor Replacement .
Resistance of the wheel speed sensor will increase with an increase in sensor temperature. Refer to the ABS Diagnostic Specifications for temperature/resistance values.
Test Description
The numbers below refer to the steps in the diagnostic table:
-
This step checks the resistance of the right front wheel speed sensor circuit.
-
This step checks for continuity in the right front wheel speed sensor harness.
-
This step checks the resistance of the right front wheel speed sensor.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Diagnostic System Check performed? | -- | Go to Step 2 | |
Is the resistance measurement within the specified range? | -- | Go to Step 5 | Go to Step 3 | |
Is the resistance measurement within the specified range? | 0-2 ohms | Go to Step 4 | Go to Step 10 | |
Using a J 39200 , measure the resistance between terminals A and B of the right front wheel speed sensor connector. (Refer to ABS Diagnostic Specifications for applicable sensor resistance values. The values in these tables are for the resistance of the sensor, not the air temperature.) Is the resistance measurement within the specified range? | -- | Go to Step 7 | Go to Step 11 | |
5 | Inspect the 4-way EBCM harness connector for poor terminal contact or corrosion. Does damage or corrosion exist? | -- | Go to Step 8 | Go to Step 6 |
6 |
Does the DTC set as a current DTC? | -- | Go to Step 9 | Go to Step 7 |
7 |
Refer to Diagnostic Aids for more information. Is the repair complete? | -- | -- | |
8 | Make necessary repairs to the 4-way EBCM harness connector. Refer to Connector Repairs . Is the repair complete? | -- | -- | |
9 | Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Is the repair complete? | -- | -- | |
10 | Repair the open or high resistance in CKT 833 or CKT 872. Refer to Wiring Repairs . Is the repair complete? | -- | -- | |
11 | Replace the wheel speed sensor. Refer to Wheel Speed Sensor Replacement . Is the repair complete? | -- | -- |
