GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2002 🢒 Alero Export 🢒 DTC 🢒 DTC C1287

Circuit Description

The Steering Position Sensor is a 5 volt sensor that is used by the Variable Effort Steering (VES) system to detect rapid steering wheel movement. The valid voltage range of the sensor is 0.39-4.86 V. The signal circuit voltage will increase and decrease within the valid voltage range as the steering wheel is turned. The Electronic Brake Control Module (EBCM) monitors the signal voltage from the steering position sensor. If the EBCM detects rapid steering wheel movement, during abrupt driving maneuvers, less current is commanded to the VES actuator to provide full steering assists.

Conditions for Running the DTC

The ignition is on, and ignition voltage is between 10.5-17.0 volts.

Conditions for Setting the DTC
    • The steering position sensor signal voltage is less than 0.39 V or greater than 4.89 V for more than 2 seconds.
    • The steering position sensor signal voltage changes by more than 2.5 V within 0.02 seconds.

Action Taken When the DTC Sets
    • A DTC C1287 is stored in memory.
    • The VES system is disabled for the remainder of the ignition cycle.

Conditions for Clearing the DTC
    • A current DTC will clear when the malfunction is no longer present.
    • A history DTC will clear after 100 consecutive malfunction free ignition cycles.
    • Using the scan tool

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Tests if the sensor is with in the valid voltage range.

    2.

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

    3.

  3. Tests for the proper operation of the signal 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.

    4.

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

    5.

  5. Tests for a high resistance or an open in the low reference circuit.

    6.

  6. Perform the setup procedure after EBCM replacement.

Step

Action

Value(s)

Yes

No

Schematic Reference: Steering Assist Schematics

1

Did you perform the Variable Effort Steering Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Variable Effort Steering

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With the scan tool, observe the Steering Position Sensor data parameter in the VES data list.

Does the scan tool indicate that the Steering Position Sensor data parameter is within the specified range?

0.39 V-4.86 V

Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the steering position sensor harness connector.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the Steering Position Sensor data parameter.

Does the scan tool indicate that the Steering Position Sensor data parameter is less than the specified value?

0.39 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 and the signal circuit of the steering position sensor harness connector.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the Steering Position Sensor data parameter.

Does the scan tool indicate that the Steering Position Sensor data parameter is greater than the specified value?

4.86 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 and the low reference circuit of the steering position sensor harness connector.

Does the voltage measure less than 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.
  3. Measure the resistance from the low reference circuit of the steering position 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 steering position sensor for a short to voltage. Refer to Testing for a Short to Voltage 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 steering position sensor for a short to ground, 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 9

9

Test the signal circuit of the steering position sensor for a short to ground, 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

10

Test the signal circuit of the steering position sensor for a short to voltage. Refer to Testing for a Short to Voltage and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 13

11
  1. Disconnect the EBCM.
  2. Test the low reference circuit of the steering position 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 steering position 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 steering position sensor. Refer to Steering Wheel Position Sensor or Steering Shaft Lower Bearing Replacement .

Did you complete the replacement?

--

Go to Step 16

--

15

Important: Perform the set up procedure for the EBCM .

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

Did you complete the replacement?

--

Go to Step 16

--

16
  1. Use the scan tool in order to clear the DTCs.
  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