Circuit Description
As the wheel is rotated, the speed sensor produces an alternating current (AC) voltage that increases with wheel speed. The electronic brake control module (EBCM) uses the frequency of the AC signal to calculate wheel speed. The speed sensor is connected to the EBCM by a twisted pair of wires. Twisting reduces noise susceptibility that may cause a DTC to set.
Conditions for Setting the DTC
DTC C0033 can be set anytime the key is ON and the EBCM has detected an open, short to ground, or a short to battery on the right front wheel speed circuit.
Action Taken When the DTC Sets
| • | The solenoid relay opens, removing power to the pump motor and solenoids. |
| • | DTC C0033 is stored. |
| • | The antilock brake system (ABS) is disabled, ABS warning lamp turns ON. |
Conditions for Clearing the DTC
| • | If the conditions that set DTC C0033 are no longer present, the DTC may be cleared by using the proper scan tool. |
| • | The DTC that has not occurred in 100 drive cycles will be cleared from history data. |
Diagnostic Aids
Thoroughly inspect the wiring and connectors when diagnosing intermittent DTCs. This will include the following:
| • | Removal of the protective conduit and inspection for wiring for damage, shorts, and contamination |
| • | Inspection for improperly formed and/or damaged terminals |
| • | Checking terminal contact, retention force, by using a spare male/female terminal |
| • | Removal of the terminals from the connectors to check for proper terminal to wire crimp |
If the drivers comments reflect that the ABS warning lamp is ON only during moist environmental changes such as rain, snow, vehicle wash, etc., all wheel speed sensor circuitry should be thoroughly inspected for signs of water intrusion. If the DTC is not current, simulate the effects of water intrusion. Use the following procedure. Spray the suspected area with a 5 percent saltwater solution. Then test drive the vehicle over various road surfaces such as bumps, turns, etc. above 24 km/h (15 mph). If the DTC sets then replace the suspected harness and or sensor.
When measuring wheel speed sensor resistance ensure the vehicle is at room temperature. Resistance will increase with temperature.
Failure to perform the previous steps carefully and fully can result in misdiagnosis, unnecessary component replacement, and reoccurrence of DTC C0033.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check-ABS? | -- | Go to Step 2 | |
2 |
Is any physical damage noted? | -- | Go to Step 3 | Go to Step 4 |
3 | Repair the damage to the right front wheel speed sensor, jumper harness, and/or toothed ring. Did you complete the repair? | -- | System OK | -- |
4 | Test drive the vehicle at various speeds and over various road surfaces. Did DTC C0033 reset? | -- | Go to Step 6 | Go to Step 5 |
5 | DTC C0033 is intermittent. Refer to Diagnostic Aids. Did you find and correct the condition? | -- | System OK | -- |
6 |
Important: Resistance will vary with temperature. Does the resistance measure within the specified range? | 800-1600 ohms | Go to Step 8 | Go to Step 7 |
7 | Replace the right front wheel speed sensor. Did you complete the replacement? | -- | System OK | -- |
8 |
Does the resistance measure OL, open circuit? | -- | Go to Step 9 | Go to Step 7 |
9 |
Does the resistance measure less than the specified value? | 2 ohms | Go to Step 11 | Go to Step 10 |
10 | Repair the open or high resistance between terminals A07 and 2. Did you complete the repair? | -- | System OK | -- |
11 |
Does the resistance measure less than the specified value? | 2 ohms | Go to Step 13 | Go to Step 12 |
12 | Repair the open or high resistance between terminals A07 and 2. Did you complete the repair? | -- | System OK | -- |
13 |
Does the voltage measure less than the specified value? | 1 V | Go to Step 15 | Go to Step 14 |
14 | Repair the source open or high resistance between terminals A08 and 1. Did you complete the repair? | -- | System OK | -- |
15 |
Does the voltage measure less than the specified value? | 1 V | Go to Step 17 | Go to Step 16 |
16 | Repair the short to voltage between terminals A07 and 2. Did you complete the repair? | -- | System OK | -- |
17 |
Does the resistance measure OL, open circuit? | -- | Go to Step 19 | Go to Step 18 |
18 | Repair the short to ground between terminals A08 and 1. Did you complete the repair? | -- | System OK | -- |
19 |
Does the resistance measure OL, open circuit? | -- | Go to Step 21 | Go to Step 20 |
20 | Repair the short to ground between terminals A07 and 2. Did you complete the repair? | -- | System OK | -- |
21 |
Does the resistance measure OL, open circuit? | -- | Go to Step 23 | Go to Step 22 |
22 | Repair the short between the 2 circuits. Did you complete the repair? | -- | System OK | -- |
23 |
Did DTC C0033 reset? | -- | Go to Step 24 | System OK |
24 | Replace the EBCM. Did you complete the replacement? | -- | System OK | -- |
