| Table 1: | WSS Temperature vs. Sensor Resistance |
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
The wheel speed signal for all sensors is above 19 km/h (12 mph) with brake released, or 32 km/h (20 mph) with brake applied, with a sudden loss of one signal for 15 ms.
Action Taken When the DTC Sets
| • | The ABS indicator lamp turns on |
| • | The ABS disables |
DTC C0227 is Condition Latched for the first two occurrences, Ignition Latched thereafter.
DTC C0227 is a DRP non critical malfunction. If another front WSS DTC sets before this DTC is investigated and cleared, this will become a DRP Critical malfunction and the BRAKE indicator lamp will also turn on.
Conditions for Clearing the DTC
| • | Repair the conditions responsible for setting the DTC |
| • | Use the Scan Tool Clear DTCs function |
| • | A Condition Latched DTC may exist momentarily, or constantly. In either case, the DTC will be stored in the EBCM memory until it is repaired, and/or the DTC is cleared. After the DTC is repaired and/or cleared and the ignition is turned to ON, the ABS lamp will remain lit until the EBCM completes a power-up self test. This test concludes when the vehicle has reached a speed of greater than 13 km/h (8 mph) and the wheel speed inputs have been checked by the EBCM. |
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 |
If the customer says that the ABS indicator lamp is on only during humid conditions such as rain, snow, or vehicle wash, then thoroughly inspect all wheel speed sensor circuits for signs of water intrusion. Use the following procedure:
- Spray the suspected area with a 5% salt water solution (two teaspoons of salt to 12 oz. of water)
- Drive the vehicle above 24 km/h (15 mph) for at least 30 seconds
If the DTC returns, replace the suspected 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 following table for temperature/resistance values.
°C | °F | Ohms |
|---|---|---|
Temperature vs Resistance Values (Approximate) | ||
-40 to 4 | -40 to 40 | 702 to 1060 |
5 to 43 | 41 to 110 | 855 to 1230 |
44 to 93 | 111 to 200 | 1000 to 1440 |
94 to 150 | 201 to 302 | 1170 to 1661 |
Test Description
The numbers below refer to the steps in the diagnostic table:
-
This step checks for the proper wheel speed sensor voltage output.
-
This step uses the wheel speed sensor resistance check to help isolate an intermittent connection.
-
This step checks to see if the DTC will set again even after the initial checks were made.
-
This step checks for proper wheel speed sensor resistance.
-
This step checks for proper mounting and orientation of the wheel speed sensor.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Diagnostic System Check performed? | -- | Go to Step 2 | |
2 |
Are all connections clean and tight? | -- | Go to Step 3 | Go to Step 8 |
Is the voltage measurement within the specified range? | .6 - 1 VAC | Go to Step 4 | Go to Step 7 | |
Using a J 39200 , measure the resistance between terminals A2 and B2 of the 16-way EBCM harness connector by probing between terminals 2 and 10. Wiggle the WSS harness in various locations between the sensor and the EBCM while performing this measurement. Is the resistance measurement within the specified range without fluctuation when the harness is wiggled? (Refer to the WSS Temperature vs. Resistance table for applicable sensor resistance values. The values in this table are for the temperature of the sensor, not the air temperature.) | -- | Go to Step 5 | Go to Step 6 | |
Does DTC C0227 set as a current DTC? | -- | Go to Step 7 | Go to Step 11 | |
Is the resistance measurement within the specified range? (Refer to the WSS Temperature vs. Resistance table for applicable sensor resistance values. The values in this table are for the temperature of the sensor, not the air temperature.) | -- | Go to Step 9 | Go to Step 10 | |
Is the wheel speed sensor securely mounted? | -- | Go to Step 13 | Go to Step 12 | |
8 | Make necessary repairs to the 16-way EBCM harness connector. Refer to Repairing Connector Terminals . Is the repair complete? | -- | -- | |
9 | Repair the open, high resistance or short in CKTs 830 or 873. Is the repair complete? | -- | -- | |
10 | Replace the left front wheel speed sensor. Refer to Wheel Speed Sensor Replacement . Is the repair complete? | -- | -- | |
11 | Malfunction is intermittent. Inspect all connectors for damage which may result in high resistance when all components are connected. Refer to Diagnostic aids for more information. Repair all damage found. Is the repair complete? | -- | -- | |
12 | Make necessary repairs. Refer to Wheel Speed Sensor Replacement . Is the repair complete? | -- | -- | |
13 | Replace the Electronic Brake Control Module. Refer to Electronic Brake Control Module Replacement . Is the repair complete? | -- | -- |
