GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1999 🢒 S10 - Electric 🢒 Steering 🢒 Power Steering System 🢒 Electro-Hydraulic Power Steering Pump Electrical Test

Step

Action

Value(s)

Yes

No

Tools Required

    • J 42502 Digital Insulation Tester
    • J 39200 Digital Multimeter (DMM)
    • J 42563 P/S and A/C Compressor Electrical Tester

1

Did you perform the Electro-Hydraulic P/S Pump Diagnostic System Check?

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Go to Step 2

Go to Electro-Hydraulic P/S Pump Diagnostic System Check

2

Caution: DC and AC high-voltage is present. To reduce the risk of severe shocks and burns, the high-voltage system should be disabled any time service work is being performed on or around the high-voltage system. When in doubt, always disable the high-voltage system. The 12-volt system will still be active after the high-voltage system has been disabled.

  1. Turn the ignition switch to the OFF position.
  2. Disable the high voltage system. Refer to High Voltage Disabling in Battery Pack Controls.
  3. Disconnect the P/S pump high voltage cable from the power steering control module (PSCM).

    4. Important: Ensure that the A/C compressor test lead from the P/S and A/C Compressor Electrical Tester is connected to the test port on the tester, or an incorrect test result will occur.

  4. Connect the P/S pump high voltage cable to the P/S and A/C Compressor Electrical Tester.

Did you complete this portion of the Electrical Test Setup?

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Go to Step 3

Go to Step 2

3
  1. Set the DMM to the ohmmeter setting.
  2. Connect the P/S and A/C Compressor Electrical Tester red and black banana plug to the DMM.
  3. Set the P/S and A/C Compressor Electrical Tester to the WINDING RESISTANCE & AC VOLTAGE TEST A-B position.

Is the resistance within the specified range?

3-6 ohms

Go to Step 4

Go to Step 7

4

Set the P/S and A/C Compressor Electrical Tester to the WINDING RESISTANCE & AC VOLTAGE TEST B-C position.

Is the resistance within the specified range?

3-6 ohms

Go to Step 5

Go to Step 7

5

Set the P/S and A/C Compressor Electrical Tester to the WINDING RESISTANCE & AC VOLTAGE TEST A-C position.

Is the resistance within the specified range?

3-6 ohms

Go to Step 6

Go to Step 7

6

Set the P/S and A/C Compressor Electrical Tester to the INTERLOCK TEST - COMPRESSOR (not POWER STEERING) position.

Is the resistance within the specified range?

0-1.5 ohms

Go to Step 8

Go to Step 7

7

Replace the P/S pump.

Is the repair complete?

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Go to Electro-Hydraulic P/S Pump Diagnostic System Check

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8
  1. Connect the power steering lead from the P/S and A/C Compressor Electrical Tester to the power steering control module (PSCM) so that the tester is in-line between the power steering pump and the PSCM.
  2. Set the DMM to the AC scale.
  3. Enable the high voltage system. Refer to High Voltage Enabling in Battery Pack Controls.

    4. Important: Allow the system to stabilize (approximately 5 minutes) before obtaining a reading. Do not turn the steering wheel during this test.

  4. Turn the ignition switch to the ON position.
  5. Measure the AC voltage at WINDING RESISTANCE & AC VOLTAGE TEST, A-B, B-C and A-C positions.

Are all of the readings within the specified range?

130-145 V

Go to Step 9

Go to Step 10

9
  1. Set the DMM to the AC scale.
  2. Select Hz.
  3. Set the range to 400.

    4. Important: Allow the system to stabilize (approximately 5 minutes) before obtaining a reading. Do not turn the steering wheel during this test.

  4. Turn the ignition switch to the ON position.
  5. Measure the frequency at the WINDING RESISTANCE & AC VOLTAGE TEST A-B, B-C, and A-C positions.

Are all of the readings within the specified range?

90-100 Hz

Go to Power Steering Hydraulic System Test

Go to Step 10

10

Replace the PSCM.

Is the repair complete?

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Go to Electro-Hydraulic P/S Pump Diagnostic System Check

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