DTC C1282 Yaw Rate Sensor Bias Circuit Malfunction w/JL4
Circuit Description
The vehicle stability enhancement system (VSES) is activated by the EBCM calculating the desired yaw rate and comparing it to the actual yaw rate input. The desired yaw rate is calculated from measured steering wheel position, vehicle speed, and lateral acceleration. The difference between the desired yaw rate and actual yaw rate is the yaw rate error, which is a measurement of oversteer or understeer. If the yaw rate error becomes too large, the EBCM will attempt to correct the vehicle's yaw motion by applying differential braking to the left or right front wheel.
Conditions for Running the DTC
The EBCM performs 6 different tests to detect a DTC condition. The numbers below correspond to the numbers in Conditions for Setting the DTC.
- The yaw rate sensor bias test runs with the ignition ON.
- The yaw rate sensor acceleration test runs with the ignition ON.
- The yaw rate sensor circuit test runs with the vehicle stopped or with the vehicle speed greater than 45 km/h (28 mph).
- The yaw rate isolation test runs with the following conditions:
- The above yaw rate isolation test run with the VSES active.
- The false activation test runs with the VSES active.
| • | The brake pedal is not pressed. |
| • | The ABS is not active. |
| • | The vehicle speed is greater than 5 km/h (3 mph). |
Conditions for Setting the DTC
The EBCM performs 6 different tests to detect a DTC condition. The numbers below correspond to the numbers in Conditions for Running the DTC.
- The yaw rate bias is greater than 7 degrees/second.
- The yaw rate input change is greater than 390 degrees/second/second.
- The yaw rate input voltage is less than 0.15 volts or greater than 4.85 volts for 1 second.
- The yaw rate error is greater than 10 degrees/second 30 times within a drive cycle.
- The yaw rate error is greater than 10 degrees/second for 5 seconds. Under this condition, this DTC will set along with DTC C1281.
- The yaw rate error is greater than 10 degrees/second with the vehicle speed less than 60 km/h (37 mph) and the acceleration pedal is pressed more than 25 percent of the pedal travel range for 1 second during the VSES activation. Under this condition, this DTC will set along with DTC C1281.
Action Taken When the DTC Sets
| • | The EBCM disables the VSES for the duration of the ignition cycle. |
| • | The DIC displays the SERVICE STABILITY SYSTEM message. |
| • | The ABS/TCS remains functional. |
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
| • | During diagnosis, park the vehicle on a level surface. |
| • | Check the vehicle for proper alignment. The car should not pull in either direction while driving straight on a level surface. |
| • | Find out from the driver under what conditions the DTC was set (when the DIC displayed the SERVICE STABILITY SYSTEM message). This information will help to duplicate the failure. |
| • | The Snapshot function on the scan tool can help find an intermittent DTC. |
Test Description
The number below refers to the step number on the diagnostic table.
-
Tests for the proper operation of the circuit in the low voltage range.
-
Tests for the proper operation of the circuit in the high voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to ground.
-
Tests for a short to voltage in the 5 volt reference circuit.
-
Tests for a high resistance or an open in the ground circuit.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the ABS Diagnostic System Check? | -- | Go to Step 2 | |||||||
2 |
Does the scan tool display that the Yaw Rate Sensor Input parameter is within the specified range? | 0.15-4.85 V | Go to Diagnostic Aids | |||||||
Does the scan tool indicate that the Yaw Rate Sensor Input parameter is less than the specified value? | 0.15 V | |||||||||
Does the scan tool indicate that the Yaw Rate Sensor Input parameter is greater than the specified value? | 4.85 V | |||||||||
Does the voltage measure less the specified value? | 5 V | |||||||||
Does the resistance measure less than the specified value? | 5 ohms | |||||||||
7 | Test the 5 volt reference circuit of the yaw rate sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||||||||
8 | Test the 5 volt reference circuit of the yaw rate sensor for the following conditions:
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||||||||
9 | Test the signal circuit of the yaw rate sensor for the following conditions:
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||||||||
10 | Test the signal circuit of the yaw rate sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||||||||
11 |
Important: If equipped with TIM, removing battery voltage or ground from the EBCM
will result in the following conditions.
Did you find and correct the condition? | -- | ||||||||
12 | Inspect for poor connections at the harness connector of the yaw rate sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||||||||
13 | Inspect for poor connections at the harness connector of the EBCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||||||||
14 | Replace the yaw rate sensor. Refer to Vehicle Yaw Sensor Replacement . Did you complete the replacement? | -- | -- | |||||||
15 |
Important: Perform the setup procedure for the EBCM. An unprogrammed EBCM will
result in the following conditions:
Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Did you complete the replacement? | -- | -- | |||||||
16 |
Does the DTC reset? | -- | System OK |
