Circuit Description
The speed sensors used on the front of this vehicle are multiple pole and the rear uses a single pole magnetic pickup. This sensor produces an AC signal that the EBCM uses the frequency from to calculate the wheel speed.
DTC Descriptor
This diagnostic procedure supports the following DTCs:
DTC C0245 Wheel Speed Sensor Frequency Error
Conditions for Running the DTC
| • | The ignition switch is ON. |
| • | The DTC can be set after system initialization. |
Conditions for Setting the DTC
| • | The electronic brake control module (EBCM) detects a deviation between 2 wheel speeds at either side of the vehicle greater than 6 km/h (3.75 mph) at a vehicle speed of less than 100 km/h (62 mph). |
| • | The EBCM detects a deviation between the left and right front wheel speeds of greater than 10 km/h (6.25 mph) at a vehicle speed of less than 100 km/h (62 mph). |
| • | The EBCM detects a deviation between the left and right front wheel speeds of greater than 4 km/h (2.5 mph) plus 6 percent of the vehicle speed at greater than 100 km/h (62 mph). |
This DTC will set when the EBCM cannot specifically identify which wheel speed sensor is causing the malfunction. If the EBCM can identify the specific wheel speed sensor causing the malfunction, DTC C0245 will become a history DTC, and the DTC associated with the sensor DTC C0036, DTC C0041, DTC C0046, DTC C0051, will be set concurrent with DTC C0245.
Action Taken When the DTC Sets
If equipped, the following actions occur:
| • | The EBCM disables the antilock brake system (ABS) if the exact fault can be determined and after ABS control has terminated. |
| • | A malfunction DTC will set. |
| • | The ABS indicator turns ON. |
| • | The traction control system (TCS) indicator turns ON. |
| • | The Red BRAKE Warning indicator turns ON. |
Conditions for Clearing the DTC
| • | The condition for the DTC is no longer present and the DTC is cleared with a scan tool. |
| • | The electronic brake control module (EBCM) automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles. |
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. |
| • | Thoroughly inspect any circuitry that may be causing the 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 |
| • | The following conditions may cause an intermittent malfunction: |
| - | A poor connection |
| - | Rubbed-through wire insulation |
| - | A broken wire inside the insulation |
| • | If the customer's comments reflect that the amber ABS/TCS indicator is on only during moist environmental conditions (rain, snow, vehicle wash), inspect all the wheel speed sensor circuitry for signs of water intrusion. If the DTC is not current, clear all DTCs and simulate the effects of water intrusion by using the following procedure: |
| 1. | Spray the suspected area with a five percent saltwater solution. |
Add two teaspoons of salt to twelve ounces of water to make a five percent saltwater solution.
| 2. | Test drive the vehicle over various road surfaces (bumps, turns, etc.) above 40 km/h (25 mph) for at least 30 seconds. |
| 3. | If the DTC returns, replace the suspected harness. |
| • | If an intermittent malfunction exists refer to Testing for Intermittent Conditions and Poor Connections . |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
If DTC C0245 is a history code, this step checks if a specific Wheel Speed Circuit Malfunction DTC is set concurrently with DTC C0245.
-
This step checks if the wheel speed sensor harness is routed in close proximity to the spark plug wires.
-
In this step, if the scan tool can record any erroneous wheel speed sensor signals, diagnose that sensors first.
Step | Action | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Antilock Brake System Schematics Connector End View Reference: Antilock Brake System Connector End Views | |||||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |||||||||
Is the following DTCs set concurrently with a history DTC C0245?
| Go to Step 3 | ||||||||||
3 | Inspect the wheel speed sensor (WSS) for physical damage. Is physical damage of the WSS evident? | Go to Step 4 | Go to Step 5 | ||||||||
4 | Replace the WSS. Refer to Front Wheel Speed Sensor Replacement or Rear Wheel Speed Sensor Replacement . Is the replacement complete? | Go to Step 14 | -- | ||||||||
5 | Inspect the wiring harness for physical damage. Is physical damage of the wiring harness evident? | Go to Step 6 | Go to Step 7 | ||||||||
6 | Repair the wiring harness. Refer to Wiring Repairs and Connector Repairs . Is the replacement complete? | Go to Step 14 | -- | ||||||||
Check for proper routing of the wheel speed sensor harness. Check that the wheel speed sensor harness is routed away from the spark plug wires. Refer to Harness Routing Views . Is the wheel speed sensor harness properly routed? | Go to Step 9 | Go to Step 8 | |||||||||
8 | Reroute the wheel speed sensor harness away from the spark plug wires. Is the reroute complete? | Go to Step 14 | -- | ||||||||
Did the scan tool trigger on any of the wheel speed sensors? | Go to Step 10 | Go to Step 11 | |||||||||
10 | Note which wheel speed sensor triggered the scan tool. Follow the appropriate Wheel Speed Sensor Malfunction DTC table for the wheel speed sensor that triggered. Refer to Diagnostic Trouble Code (DTC) List - Vehicle . Is the repair complete? | Go to Step 14 | -- | ||||||||
11 |
Does the DTC reset as a current DTC? | Go to Step 13 | Go to Step 12 | ||||||||
12 | Malfunction is intermittent. Inspect all connectors and harnesses for damage that may result in an open or high resistance when connected. Refer to Connector Repairs and Wiring Repairs . Is the repair complete? | Go to Step 14 | -- | ||||||||
13 | Replace the electronic brake control module (EBCM). Refer to Control Module References for replacement, setup, and programming. Is the replacement complete? | Go to Step 14 | -- | ||||||||
14 |
Does the DTC reset? | Go to Step 2 | System OK | ||||||||
