Circuit Description
The EBCM triggers a yaw rate sensor test every 40 milliseconds and switches the sensor into test mode. The EBCM sends a test signal to the sensor via the test circuit. When the test is run, the measured yaw rate from the sensor to the EBCM must be in the range of 25 degrees per second +/- 7 degrees per second. At standstill, the vehicle yaw rate is zero. The yaw rate signal at standstill is called the offset. If calibration at standstill is not possible, a quick calibration during driving is done. The measured yaw rate is calibrated to a calculated reference yaw rate signal. Yaw rate sensor sensitivity is estimated by comparison of the reference yaw rate and the measured yaw rate during cornering.
Steering angle centering is the process by which the EBCM calibrates the steering sensor output so that the output reads zero when the steering wheel is centered. The PCS steering angle sensor centering process is performed manually.
Conditions for Running the DTC
| • | The ignition is ON. |
| • | The vehicle speed is greater than 40 km/h (25 mph). |
Conditions for Setting the DTC
A malfunction is detected if one or more of the following conditions exist:
| • | The yaw rate sensor signal is out of range for 220-420 milliseconds. |
| • | The yaw rate sensor signal at standstill which is called the offset is outside the allowed range of +/- 8 degrees per second. |
| • | The sensor sensitivity which is estimated by comparing the reference yaw rate and the measured yaw rate during cornering, is outside a predetermined range. |
| • | The yaw rate is changing at a rate greater than 6-23 degrees per second per 40 milliseconds. |
Action Taken When the DTC Sets
If equipped, the following actions occur:
| • | The EBCM disables the TCS/VSES for the duration of the ignition cycle. |
| • | A malfunction DTC is set. |
| • | The ANTI-LOCK indicator turns ON. |
| • | The TRAC Off indicator turns ON. |
| • | The PCS indicator turns ON. |
Conditions for Clearing the DTC
| • | The condition for the DTC is no longer present. |
| • | A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present. |
| • | Using a scan tool |
Diagnostic Aids
The following conditions may cause a malfunction:
| • | Malfunctioning lateral accelerometer |
| • | Malfunctioning EBCM |
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
-
Checks to see if steering angle sensor is centered.
-
Checks for specified voltage on the lateral accelerometer signal circuit.
-
Checks for specified voltage on the yaw rate signal circuit.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: Antilock Brake System Schematics | ||||
1 | Did you perform the ABS Diagnostic System Check? | -- | Go to Step 2 | |
Perform the steering angle sensor centering procedure. Refer to Steering Angle Sensor Centering . Did you successfully complete the centering procedure? | Go to Step 3 | Go to Step 7 | ||
Is the voltage within the specified value? | 2.3- 2.7 V | Go to Step 4 | Go to Step 8 | |
Using the DMM, measure the voltage between pin 26 and pin 15 of the J 39700 universal pinout box. Is the voltage within the specified value? | 2.3- 2.7 V | Go to Step 5 | Go to Step 8 | |
5 |
Does the DTC reset? | -- | Go to Step 6 | Go to Diagnostic Aids |
6 | Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Did you complete the replacement? | -- | Go to Step 9 | -- |
7 | Replace the steering angle sensor. Refer to Steering Shaft, Lower Bearing, and Jacket - Disassemble - Off Vehicle in Steering Wheel and Column - Tilt. Did you complete the replacement? | -- | Go to Step 9 | - |
8 | Replace the vehicle yaw/lateral accelerometer sensor. Refer to Vehicle Yaw Sensor with Vehicle Lateral Accelerometer Replacement . Did you complete the repair? | -- | Go to Step 9 | - |
9 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
