Stability System Not Ready Indicator Always On w/JL9
Diagnostic Instructions
Circuit Description
The instrument panel cluster (IPC) illuminates the stabilitrak indicator during the IPC bulb check or when the electronic brake control module (EBCM) sends a serial data message to the IPC commanding the indicator ON. The 5 inputs to the electronic
brake control module (EBCM), which are used solely for vehicle stability enhancement, are the longitudinal accelerometer, lateral accelerometer, yaw rate sensor, master cylinder pressure sensor, and the steering wheel position sensor. The EBCM must detect valid
inputs from all 5 sources during the initialization period in order to enable the vehicle stability enhancement system (VSES). Initialization must occur during the first 3 000 meters of vehicle travel or 1 000 meters of straight
vehicle travel. If initialization cannot be achieved during this time period, the VSES remains inactive and the stability system not ready indicator is illuminated. The EBCM does not attempt to reinitialize until the next ignition cycle. One or more DTCs often
set, shortly after an unsuccessful initialization attempt, indicating the root cause of the failure. If this occurs, the stability system not ready indicator is no longer illuminated.
Reference Information
Schematic Reference
Antilock Brake System Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
ABS Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References
for Scan Tool Information
Circuit Verification
Ignition ON, observe the scan tool VSES EBCM steering wheel position sensor SWPS Phase A and SWPS Phase B parameters. The reading per SWPS should change from Low to High and change with the rotation of the steering wheel.
Diagnostic Aids
| • | If the customer concern is that the stability system disabled message is displayed intermittently, communicate with the customer to determine what driving conditions are being experienced at the time the message is displayed. The EBCM may be unable
to successfully initialize the system during operation on very winding roads. Initialization may also be unsuccessful if pressure is continuously applied to the brake pedal during the initialization period. |
| • | If the message is displayed due to any of the above conditions, no diagnosis or repair of the VSES is required. |
| • | Check if any of the following vehicle stability enhancement system (VSES) history DTCs are stored in history. |
Do any of the above DTCs set as a current DTC. Refer to
Diagnostic Trouble Code (DTC) List - Vehicle
.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the steering wheel position sensor.
- Ignition OFF, test for less than 1.0 ohm between the EBCM low reference circuit terminals 11 and 28 and ground.
| ⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the EBCM. |
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 31 and ground.
| ⇒ | If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the EBCM. |
| ⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the EBCM. |
- Verify the scan tool Digital SWPS Phase A and Phase B minimum value is less then Low.
| ⇒ | If greater than the specified range, test the EBCM signal circuit terminal 6 for a short to voltage. If the circuit tests normal, replace the EBCM. |
- Install a 3A fused jumper wire between the signal circuit terminal 6 and the 5-volt reference circuit terminal 31. Verify the scan tool SWPS Signal A is greater than 5-volts.
| ⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the EBCM. |
- If all circuits test normal, test or replace the Steering Wheel Speed Position Sensor.
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
Stability System Not Ready Indicator Always On w/JL4
Diagnostic Instructions
Circuit Description
The instrument panel cluster (IPC) illuminates the stabilitrak indicator during the IPC bulb check or when the electronic brake control module (EBCM) sends a serial data message to the IPC commanding the indicator ON. The 5 inputs to the electronic
brake control module (EBCM), which are used solely for vehicle stability enhancement, are the longitudinal accelerometer, lateral accelerometer, yaw rate sensor, master cylinder pressure sensor, and the steering wheel position sensor. The EBCM must detect valid
inputs from all 5 sources during the initialization period in order to enable the vehicle stability enhancement system (VSES). Initialization must occur during the first 3 000 meters of vehicle travel or 1 000 meters of straight
vehicle travel. If initialization cannot be achieved during this time period, the VSES remains inactive and the stability system not ready indicator is illuminated. The EBCM does not attempt to reinitialize until the next ignition cycle. One or more DTCs often
set, shortly after an unsuccessful initialization attempt, indicating the root cause of the failure. If this occurs, the stability system not ready indicator is no longer illuminated.
Reference Information
Schematic Reference
Antilock Brake System Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
ABS Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for Scan Tool Information
Circuit Verification
Ignition ON, observe the scan tool VSES EBCM steering wheel position sensor SWPS Phase A and SWPS Phase B parameters. The reading per SWPS should change from Low to High and change with the rotation of the steering wheel.
Diagnostic Aids
| • | If the customer concern is that the stability system disabled message is displayed intermittently, communicate with the customer to determine what driving conditions are being experienced at the time the message is displayed. The EBCM may be unable
to successfully initialize the system during operation on very winding roads. Initialization may also be unsuccessful if pressure is continuously applied to the brake pedal during the initialization period. |
| • | If the message is displayed due to any of the above conditions, no diagnosis or repair of the VSES is required. |
| • | Check if any of the following vehicle stability enhancement system (VSES) history DTCs are stored in history. |
Do any of the above DTCs set as a current DTC. Refer to
Diagnostic Trouble Code (DTC) List - Vehicle .
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the steering wheel position sensor.
- Ignition OFF, test for less than 1.0 ohm between the EBCM low reference circuit terminals 1 and 25 and ground.
| ⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the EBCM. |
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 31 and ground.
| ⇒ | If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the EBCM. |
| ⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the EBCM. |
- Verify the scan tool Digital SWPS Phase A and Phase B minimum value is less then Low.
| ⇒ | If greater than the specified range, test the EBCM signal circuit terminal 6 for a short to voltage. If the circuit tests normal, replace the EBCM. |
- Install a 3A fused jumper wire between the signal circuit terminal 6 and the 5-volt reference circuit terminal 31. Verify the scan tool SWPS Signal A is greater than 5-volts.
| ⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the EBCM. |
- If all circuits test normal, test or replace the Steering Wheel Speed Position Sensor.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
