Circuit Description
The vehicle uses the longitudinal accelerometer input when calculating the desired traction control. The usable output voltage range for the longitudinal accelerometer 0.48-4.84 volts. The scan tool will report zero longitudinal acceleration as 2.5 volts with no sensor bias present.
The longitudinal accelerometer sensor bias compensates for sensor mounting alignment errors and electronic signal errors.
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
| • | If during stable driving conditions, the longitudinal accelerometer signal becomes larger than 0.26 g, the EBCM controller will disregard the signal so that a false EBCM intervention is prevented. A malfunction is detected if this condition continues for more than two seconds. |
| • | Under normal driving conditions, the long time filtered driving direction is straight ahead. The long time filtered longitudinal accelerometer value is called the offset. If the offset value is higher than 0.23 g, a malfunction is detected. Malfunction time depends on driving distance, vehicle speed and the amount of malfunctioning longitudinal accelerometer signal. |
| • | The longitudinal accelerometer signal is limited to an electrical stop of 1.8 g. If the longitudinal accelerometer signal is greater than 1.5 g for more than 500 milliseconds, a malfunction is detected. |
| • | At a standstill, the range of the longitudinal accelerometer signal is less than 0.7 g. If the longitudinal accelerometer signal is greater than 0.7 g at standstill, a malfunction is detected. |
| • | longitudinal accelerometer signal cannot change rapidly under normal driving conditions. If the longitudinal accelerometer signal is changing faster than 55 g per second, a malfunction is detected. |
Action Taken When the DTC Sets
| • | A malfunction DTC is set |
| • | TCS is disabled for the duration of the ignition cycle |
| • | ABS remains functional |
| • | ABS lamp indicators turn 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
Any circuitry that is suspected of causing an intermittent complaint should be thoroughly checked for improper mating, improperly formed or damaged terminals, poor terminal to wiring connections, or physical damage to the wiring harness. If an intermittent condition exists, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: Antilock Brake System Schematics Connector End View Reference: Antilock Brake System Connector End Views | ||||
1 | Did you perform the ABS Diagnostic System Check? | -- | Go to Step 2 | |
Is the voltage within the specified value? | 2.3-2.7 V | Go to Step 3 | Go to Step 6 | |
Using the DMM, measure the voltage between pin 28 and pin 15 of the J 39700 universal pinout box. Is the voltage within the specified value? | 4.5-5 V | Go to Step 4 | Go to Step 6 | |
4 |
Does the DTC reset? | -- | Go to Step 5 | Go to Diagnostic Aids |
5 | Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Did you complete the replacement? | -- | Go to Step 7 | -- |
6 | Replace the vehicle longitudinal accelerometer sensor. Refer to Longitudinal Accelerometer Replacement . Did you complete the repair? | -- | Go to Step 7 | -- |
7 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
