Circuit Description
The electronic brake control module (EBCM) receives multiple direct inputs from the steering wheel position sensor. These circuits include 2 digital square wave input signals A and B. Phase A or B should toggle high and low every 2 degrees of steering wheel rotation. The EBCM also receives one analog steering wheel position input on the steering wheel position sensor signal 1 circuit, and is compared to the digital circuits for fault detection. The analog portion of the steering wheel position sensor is supplied a 5-volt reference and low side return circuits from the EBCM. Ignition voltage and ground circuits are supplied directly to the digital portion of the steering wheel position sensor.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC C0455 Front Steering Position Sensor Circuit
Conditions for Running the DTC
| • | The ignition is ON. |
| • | The vehicle stability enhancement system (VSES) sensors have been successfully initialized. Refer to ABS Description and Operation for a complete explanation of VSES sensor initialization. |
Conditions for Setting the DTC
Any of the following conditions may cause the DTC to set:
| • | The digital steering wheel position signal does not correlate with the analog steering wheel position signals. |
| • | When driven forward in a straight line, the centered steering angle differs by more than 30 degrees from the centered steering angle when the sensors are initialized. |
| • | The EBCM detects an erratic signal from steering wheel position signal A or signal B. |
| • | The EBCM detects an open or shorted steering wheel position analog signal. |
| • | The EBCM detects an erratic steering wheel position analog signal. |
| • | The EBCM detects an open or shorted steering wheel position signal A or signal B, after having received a valid signal during the same ignition. |
Action Taken When the DTC Sets
| • | The EBCM disables the VSES. |
| • | The stability system caution indicator is illuminated. |
Conditions for Clearing the DTC
The condition for setting the DTC is no longer present and you use the scan tool Clear DTCs function.
Diagnostic Aids
| • | DTC C0455 may be falsely set if you did not turn OFF the ignition for 5 seconds after clearing DTCs from the EBCM. This is why all diagnostic tables which apply to this system always instruct you to turn OFF the ignition for 5 seconds after clearing DTCs. If this DTC has set after you cleared DTCs from the EBCM or used the scan tool to clear all DTCs from all modules and you did not cycle the ignition afterward, it is likely that no actual malfunction exists. |
| • | If the DTC does not reset during step 2 or 3 of the diagnostic procedure, the stability system not ready indicator may be displayed due to an unsuccessful initialization. This occurs if the EBCM does not receive any signal from one or both of the digital inputs during the entire ignition cycle. |
| • | Inspect the vehicle for proper wheel alignment. Ensure the vehicle does not pull toward the left or right while driving straight forward on a level surface. |
| • | Communicate with the customer to determine the conditions under which the instrument panel cluster (IPC) illuminates the stability system caution indicator. Learning the conditions under which the DTC sets may help you duplicate the failure. |
| • | Use the Snapshot function on the scan tool in order to assist you in locating an intermittent malfunction. |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Values | 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 | |||||||||||
|
Important: Center the steering wheel before proceeding with this step. Do not rotate the steering wheel while performing this step.
Does the DTC set? | -- | Go to Step 3 | Go to Step 10 | |||||||||||
3 |
Does the scan tool indicate that the steering wheel position sensor data parameter is less than specified value? | 0.15 V | Go to Step 4 | Go to Step 9 | ||||||||||
4 |
Does the scan tool indicate that the steering wheel position sensor data parameter is greater than specified value? | 4.75 V | Go to Step 5 | Go to Step 6 | ||||||||||
5 | Use a DMM to measure the voltage between the steering wheel position 5-volt reference circuit and the steering wheel position low reference circuit. Does the voltage measure greater than the specified value? | 4.75 V | Go to Step 17 | Go to Step 8 | ||||||||||
6 | Test the 5-volt reference circuit of the steering wheel position sensor for an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 7 | ||||||||||
7 | Test the signal circuit of the steering wheel position sensor for an open or a short to ground. Refer to Testing for Short to Ground and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 17 | ||||||||||
8 | Test the low reference circuit of the steering wheel position sensor for an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 17 | ||||||||||
9 | Test the signal circuit of the steering wheel position sensor for a short to voltage. Refer to Testing for Short to Ground and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 17 | ||||||||||
10 | Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC set? | -- | Go to Step 11 | Go to Diagnostic Aids | ||||||||||
11 |
Does the scan tool display an Analog SWPS Signal within the specified range? | 2.3-2.7 V | Go to Step 12 | Go to Step 17 | ||||||||||
12 |
Does only one signal toggle? | -- | Go to Step 13 | Go to Step 14 | ||||||||||
13 |
Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 14 | ||||||||||
14 | Test the battery positive voltage circuit to the steering wheel position sensor for an intermittent open. Refer to Testing for Electrical Intermittents and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 15 | ||||||||||
15 | Test both of the steering wheel position sensor ground circuits for an intermittent open. Refer to Testing for Electrical Intermittents and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 16 | ||||||||||
16 | Inspect for poor connections at the harness connector of the steering wheel position sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 18 | ||||||||||
17 | Inspect for poor connections at the harness connector of the EBCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 19 | ||||||||||
18 | Replace the steering wheel position sensor. Refer to Steering Wheel Position Sensor or Steering Shaft Lower Bearing Replacement . Did you complete the replacement? | -- | Go to Step 20 | -- | ||||||||||
19 |
Important: Following EBCM replacement, perform the setup procedure for the EBCM. Use the scan tool to perform the Tire Size Calibration procedure. Replace the EBCM. Refer to Control Module References . Did you complete the replacement? | -- | Go to Step 20 | -- | ||||||||||
20 |
Does the DTC reset? | -- | Go to Step 2 | System OK | ||||||||||
