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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2000 🢒 Corvette 🢒 DTC 🢒 DTC C1285 Lateral Accelerometer Sensor Circuit Malfunction

Object Number: 568073 Size: MF
ABS Components
Antilock Brake System Schematics

Circuit Description

The output of the Lateral Accelerometer is measured by the EBCM any time ignition is present. The usable output voltage range for the Lateral Accelerometer is 0.25 - 4.75 volts. The scan tool will report a zero lateral accelerometer signal of 2.5 volts if no sensor bias (offset) is present and the vehicle is on a flat surface.

Conditions for Setting the DTC

DTC C1285 can be set any time the ignition is present and the Lateral Accelerometer voltage is less than 0.15 volts or greater than 4.85 volts for approximately 1 second or more.

Action Taken When the DTC Sets

ABS and TCS remain enabled, Active Handling is disabled.

    • Indicators that turn on:
        Car Icon (TCS indicator)
    • Messages displayed on the DIC:
        Service Active HNDLG

Conditions for Clearing the DTC
    • Condition for DTC is no longer present and scan tool clear DTC function is used.
    • Fifty ignition cycles have passed with no DTCs detected.

Diagnostic Aids
    • It is very important to find out from the driver when the code was set (when the SERVICE ACTIVE HNDLG message was activated). This information may help to duplicate the failure.
    • It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction. Check connector C102 RH side rear of engine compartment for water intrusion or missing plugs, and that the connector is oriented horizontal to prevent water intrusion.
    • An intermittent malfunction is most likely caused by a poor connection, rubbed through wire insulation, or a wire that is broken inside the insulation. Refer to Testing for Electrical Intermittents in Wiring Systems.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. This step checks for the EBCM pull up voltage.

    2.

  2. This step checks for the proper Lateral Accelerometer Sensor signal being sent to the EBCM.

    3.

  3. This step checks if the EBCM can properly interpret the Lateral Accelerometer Sensor signal.

DTC C1285 Lateral Accelerometer Sensor Circuit Malfunction

Step

Action

Value(s)

Yes

No

1

Was the Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check - ABS

2
  1. Turn the ignition switch to the OFF position.
  2. Disconnect the EBCM connector.
  3. Install J 39700 Universal Pinout Box using the J 39700-25 cable adapter to the EBCM harness connector only.
  4. Using J 39200 DMM, measure the resistance between J 39700 terminals 22 and B.

Is the resistance within the range specified in the value(s) column?

OL (infinite)

Go to Step 4

Go to Step 3

3

Repair CKT 1338 for a short to ground. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

4

Using J 39200 DMM, measure the resistance between J 39700 terminals 11 and B.

Is the resistance within the range specified in the value(s) column?

OL (infinite)

Go to Step 6

Go to Step 5

5

Repair CKT 1056 for a short to ground. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

6
  1. Disconnect the Yaw Rate Sensor, Lateral Accelerometer, Brake Pressure Sensor, and the SWPS connectors.
  2. Using J 39200 DMM, measure the resistance between J 39700 terminals 11 and 27.

Is the resistance within the range specified in the value(s) column?

OL (infinite)

Go to Step 8

Go to Step 7

7

Repair short between CKT(s) 556 and 1056. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

8

Using J 39200 DMM, measure the resistance between J 39700 terminals 11 and 22.

Is the resistance within the range specified in the value(s) column?

OL (infinite)

Go to Step 10

Go to Step 9

9

Repair short between CKT(s) 1056 and 1338. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

10

Using J 39200 DMM, measure the resistance between J 39700 terminals 27 and 22.

Is the resistance within the range specified in the value(s) column?

OL (infinite)

Go to Step 12

Go to Step 11

11

Repair short between CKT(s) 1338 and 556. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

12
  1. Turn the ignition switch to the ON position, engine OFF.
  2. Using J 39200 DMM, measure the voltage between J 39700 terminals 22 and B.

Is the voltage within the range specified in the value(s) column?

Greater than 1 V

Go to Step 13

Go to Step 14

13

Repair CKT 1338 for a short to voltage. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

14

Using J 39200 DMM, measure the voltage between J 39700 terminals 11 and B.

Is the voltage within the range specified in the value(s) column?

Greater than 1 V

Go to Step 15

Go to Step 16

15

Repair CKT 1056 for a short to voltage. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

16

Using J 39200 DMM, measure the voltage between J 39700 terminals 27 and B.

Is the voltage within the range specified in the value(s) column?

Greater than 1 V

Go to Step 17

Go to Step 18

17

Repair CKT 556 for a short to voltage. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

18
  1. Turn the ignition switch to the OFF position.
  2. Connect a fused jumper wire between terminals 22 and B of J 39700 .
  3. Using J 39200 DMM, measure the resistance between the Lateral Accelerometer harness connector terminal B and a good ground.

Is the resistance within the range specified in the value(s) column?

0-5 ohms

Go to Step 20

Go to Step 19

19

Repair CKT 1338 for an open or high resistance. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

20
  1. Connect a fused jumper wire between terminals 27 and B of J 39700 .
  2. Using J 39200 DMM, measure the resistance between the Lateral Accelerometer harness connector terminal C and a good ground.

Is the resistance within the range specified in the value(s) column?

0-5 ohms

Go to Step 22

Go to Step 21

21

Repair CKT 556 for an open or high resistance. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

22
  1. Connect a fused jumper wire between terminals 11 and B of J 39700 .
  2. Using J 39200 DMM, measure the resistance between the Lateral Accelerometer harness connector terminal A and a good ground.

Is the resistance within the range specified in the value(s) column?

0-5 ohms

Go to Step 24

Go to Step 23

23

Repair CKT 1056 for an open or high resistance. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

24

  1. Connect the J 39700-25 cable adapter between the EBCM and the EBCM harness connector.
  2. Reconnect the Lateral Accelerometer.
  3. Remove the fused jumper wire from J 39700 .
  4. Turn the ignition switch to the ON position, engine OFF.
  5. Using J 39200 DMM, measure the voltage between J 39700 terminals 11 and 27.

Is the voltage within the range specified in the value(s) column?

4.75-5.25 V

Go to Step 25

Go to Step 29

25

Using J 39200 DMM, measure the voltage between J 39700 terminals 22 and 27.

Is the voltage within the range specified in the value(s) column?

2.35-2.65 V

Go to Step 26

Go to Step 27

26

Using a scan tool read the Lateral Accelerometer value in volts.

Is the voltage within the range specified in the value(s) column?

2.0-3.0 V

Go to Step 27

Go to Step 29

27

Replace the Lateral Accelerometer. Refer to Lateral Accelerometer Replacement .

Is the replacement complete?

--

Go to Step 28

--

28
  1. Read the diagnostic aids and conditions for setting the DTC.
  2. Reconnect all previously disconnected components.
  3. Cycle the ignition switch from the OFF to ON position.
  4. Carefully drive the vehicle above 24 km/h (15 mph) for several minutes, while monitoring a scan tool for ABS/TCS/Active Handling DTC(s).

Did DTC C1285 set as a current DTC while the vehicle was being driven?

--

Go to Step 29

Go to Diagnostic System Check - ABS

29

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

Is the replacement complete?

--

Go to Diagnostic System Check - ABS

--