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Makes 🢒 Buick 🢒 2000 🢒 LeSabre 🢒 DTC 🢒 DTC C1285 Lateral Accelerometer Sensor Circuit Malfunction

DTC C1285 Lateral Accelerometer Sensor Circuit Malfunction w/JL4


Object Number: 456438 Size: MF
ABS Components
Vehicle Stability Enhancement System (w/JL4)
Handling ESD Sensitive Parts Notice

Circuit Description

The vehicle stability enhancement system (VSES) uses the lateral accelerometer input when calculating the desired yaw rate. The usable output voltage range for the lateral accelerometer is 0.25-4.75 volts. The scan tool will report zero lateral acceleration as 2.5 volts with no sensor bias present.

The lateral accelerometer sensor bias compensates for sensor mounting alignment errors and electronic signal errors.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The lateral accelerometer input voltage is less than 0.15 volts or greater than 4.85 volts for 1 second.

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.

  1. Tests for the proper operation of the circuit in the low voltage range.

    2.

  2. 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.

    3.

  3. Tests for a short to voltage in the 5 volt reference circuit.

    4.

  4. 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

Go to Diagnostic System Check - ABS

2
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Lateral Accelerometer Input parameter in the VSES data list.

Does the scan tool display that the Lateral Accelerometer Input parameter is within the specified range?

0.15-4.85 V

Go to Diagnostic Aids

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the lateral accelerometer sensor connector.
  3. Turn ON the ignition, with the engine OFF.
  4. With the scan tool, observe the Lateral Accelerometer Input parameter.

Does the scan tool indicate that the Lateral Accelerometer Input parameter is less than the specified value?

0.15 V

Go to Step 4

Go to Step 10

4

  1. Turn OFF the ignition.
  2. Connect a 3 amp fused jumper wire between the 5 volt reference circuit of the lateral accelerometer sensor and the signal circuit of the lateral accelerometer.
  3. Turn ON the ignition, with the engine OFF.
  4. With the scan tool, observe the Lateral Accelerometer Input parameter.

Does the scan tool indicate that the Lateral Accelerometer Input parameter is greater than the specified value?

4.85 V

Go to Step 5

Go to Step 8

5

  1. Disconnect the fused jumper wire.
  2. Measure the voltage between the 5 volt reference circuit of the lateral accelerometer sensor and the ground circuit of the lateral accelerometer sensor.

Does the voltage measure less the specified value?

5 V

Go to Step 6

Go to Step 7

6

  1. Turn OFF the ignition.
  2. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
  3. Measure the resistance from the ground circuit of the lateral accelerometer sensor to a good ground.

Does the resistance measure less than the specified value?

5 ohms

Go to Step 12

Go to Step 11

7

Test the 5 volt reference circuit of the lateral accelerometer sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 13

8

Test the 5 volt reference circuit of the lateral accelerometer sensor for the following conditions:

    • An open
    • A short to ground
    • A high resistance

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 9

9

Test the signal circuit of the lateral accelerometer sensor for the following conditions:

    • An open
    • A short to ground
    • A high resistance

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 13

10

Test the signal circuit of the lateral accelerometer sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 13

11

    Important: Removing battery voltage or ground from the EBCM will result in the following conditions:

       • Loss of the TIM learned tire inflation configuration parameters
       • Set DTC C1245 Low Tire Pressure Detected
    When the diagnosis is complete, inspect the tire pressures and perform the TIM reset. Refer to Tire Inflation Monitor Resetting in Tire Pressure Monitoring.

  1. Disconnect the EBCM harness connector.
  2. Install the J 39700 universal pinout box using the J 39700-300 cable adapter to the EBCM harness connector only.
  3. Test the ground circuit of the lateral accelerometer sensor for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 13

12

Inspect for poor connections at the harness connector of the lateral accelerometer sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 14

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?

--

Go to Step 16

Go to Step 15

14

Replace the lateral accelerometer sensor. Refer to Lateral Accelerometer Replacement .

Did you complete the replacement?

--

Go to Step 16

--

15

Important: Perform the setup procedure for the EBCM. An unprogrammed EBCM will result in the following conditions:

   • Inoperative or poorly functioning DRP/ABS/TCS/VSES/VES/TIM (if equipped)
   • Set DTC C1248 EBCM Turned the Red Brake Warning Indicator On
   • Set DTC C1255m3 EBCM Internal Malfunction

Replace the EBCM. Refer to Electronic Brake Control Module Replacement .

Did you complete the replacement?

--

Go to Step 16

--

16
  1. Clear the DTCs using the scan tool.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK