GM Service Manual Online
For 1990-2009 cars only

Test Description

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

  1. Listen for an audible click when the park relay operates. Command both the ON and OFF states. Repeat the commands as necessary.

  2. Tests for voltage at the coil side of the park relay.

  3. Verifies that the Rear Integration Module (RIM) is providing ground to the park relay.

  4. Tests for voltage at the feed side of the park relay.

Step

Action

Value(s)

Yes

No

1

Did you perform the Auto Trans Shift Lock Control System Diagnostic System Check?

--

Go to Step 2

Go to A Diagnostic System Check - Automatic Transmission Shift Lock Control

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, command the park relay ON and OFF.

Does the park relay turn ON and OFF with each command?

--

Go to Step 9

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the park relay.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the park relay coil supply voltage circuit with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

--

Go to Step 4

Go to Step 8

4

  1. Connect a test lamp between the park brake relay control circuit and park relay coil supply voltage circuit of the park relay.
  2. With a scan tool, command the park relay ON and OFF.

Does the test lamp turn ON and OFF with each command?

--

Go to Step 23

Go to Step 5

5

Does the test lamp remain illuminated with each command?

--

Go to Step 7

Go to Step 6

6

Test the park brake relay control circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 25

Go to Step 21

7

Test the park brake relay control circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 25

Go to Step 21

8

Repair the park relay coil supply voltage circuit of the park relay. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 25

--

9

  1. Turn OFF the ignition.
  2. Disconnect the park relay.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the supply voltage circuit of the park relay with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

--

Go to Step 11

Go to Step 10

10

Repair the supply voltage circuit of the park relay. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 25

--

11

  1. Turn OFF the ignition.
  2. Reconnect the park relay.
  3. Disconnect the auto trans shift lock control switch.
  4. Turn ON the ignition, with the engine OFF.
  5. Probe the supply voltage circuit of the auto trans shift lock control switch with a test lamp that is connected to a good ground.
  6. With a scan tool, command the park relay ON.

Does the test lamp illuminate?

--

Go to Step 13

Go to Step 12

12

Test the supply voltage circuit of the auto trans shift lock control switch for a open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 25

Go to Step 23

13

  1. Turn OFF the ignition.
  2. Reconnect the auto trans shift lock control switch.
  3. Disconnect the auto trans shift lock control solenoid.
  4. Turn ON the ignition, with the engine OFF.
  5. Probe the supply voltage circuit of the auto trans shift lock control solenoid with a test lamp that is connected to a good ground.
  6. With a scan tool, command the park relay ON.

Does the test lamp illuminate?

--

Go to Step 17

Go to Step 14

14

Test the supply voltage circuit of the auto trans shift lock control solenoid for a open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 25

Go to Step 15

15

  1. Check the auto trans shift lock control switch adjustment.
  2. Inspect for poor connections at the auto trans shift lock control switch. 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 25

Go to Step 16

16

Replace the auto trans shift lock control switch. Refer to Stoplamp Switch Replacement (Stoplamp) in Brakes.

Did you complete the replacement?

--

Go to Step 25

--

17

  1. Connect a test lamp between the supply voltage circuit of the auto trans shift lock control solenoid and the ground circuit of the auto trans shift lock control solenoid.
  2. With a scan tool, command the park relay ON.

Does the test lamp illuminate?

--

Go to Step 18

Go to Step 24

18

  1. Check the auto trans shift lock control solenoid for proper adjustment. Refer to Automatic Transmission Shift Lock Control - Assemble - Off Vehicle in Steering.
  2. Inspect for poor connections at the auto trans shift lock control solenoid. 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 25

Go to Step 19

19

Replace the auto trans shift lock control solenoid. Refer to Automatic Transmission Shift Lock Control - Disassemble - Off Vehicle and Automatic Transmission Shift Lock Control - Assemble - Off Vehicle in Steering.

Did you complete the replacement?

--

Go to Step 25

--

20

Repair the ground circuit of the auto trans shift lock control solenoid. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 25

--

21

Inspect for poor connections at the harness connector of the RIM. 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 25

Go to Step 22

22

Replace the RIM. Refer to Rear Integration Body Control Module Replacement in Body Control System.

Did you complete the replacement?

--

Go to Step 25

--

23

Inspect for poor connections at the park relay. 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 25

Go to Step 24

24

Replace the park relay.

Did you complete the replacement?

--

Go to Step 25

--

25

Operate the vehicle within the Conditions for Running the symptom.

Does the symptom reoccur?

--

Go to Step 1

System OK