GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2002 🢒 Envoy - 4WD 🢒 Body and Accessories 🢒 Roof 🢒 Power Sunroof Inoperative

Step

Action

Value(s)

Yes

No

Schematic Reference: Sunroof Schematics

1

Did you perform the Power Sunroof Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Power Sunroof

2

Operate the power sunroof.

Does the system operate normally?

--

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3
  1. Turn the ignition ON with the engine OFF.
  2. Disconnect the sunroof switch from the harness connector.
  3. Measure the reference voltage of the sunroof switch open signal circuit at the sunroof switch harness connector to a good ground.

Does the voltage measure near the specified value?

4.5-5.5 V

Go to Step 4

Go to Step 11

4

Measure the reference voltage of the sunroof switch close signal circuit at the sunroof switch harness connector to a good ground.

Does the voltage measure near the specified value?

4.5-5.5 V

Go to Step 5

Go to Step 17

5

Measure the reference voltage between the sunroof switch close signal circuit and the low reference circuit at the sunroof switch harness connector.

Does the voltage measure near the specified value?

4.5-5.5 V

Go to Step 6

Go to Step 21

6
  1. Connect a fused jumper wire to the sunroof switch low reference circuit of the sunroof switch harness connector.
  2. Observe the position of the sunroof glass, try to operate the system by connecting the other end of the fused jumper wire to either the :
    3. • Sunroof switch open signal circuit
    • Sunroof switch close signal circuit

Does the system operate normally?

--

Go to Step 36

Go to Step 7

7
  1. Remove the fused jumper wire.
  2. Connect the sunroof switch to the harness connector.
  3. Measure the reference voltage between the sunroof switch close signal circuit and the low reference circuit at the sunroof switch harness connector.
  4. While observing the sunroof switch close signal circuit reference voltage, operate the sunroof switch to the open position.

Does the sunroof switch close signal circuit reference voltage measure near the specified value?

4.5-5.5 V

Go to Step 8

Go to Step 16

8
  1. Disconnect the sunroof module harness connector, that contains the battery positive circuit.
  2. Turn ignition to ON, engine OFF.
  3. Measure the battery positive voltage circuit at the sunroof module harness connector to a good ground.

Does the voltage measure near the specified value?

B+

Go to Step 9

Go to Step 29

9
  1. Turn the ignition OFF.
  2. Connect the sunroof module harness connector that contains the battery positive voltage circuit to the sunroof module.
  3. Disconnect the sunroof motor inline harness connector.
  4. Turn ignition ON, with engine OFF.
  5. Connect a test lamp between the sunroof motor open control and motor close control circuits at the inline harness connector, module side of the sunroof motor.

Does the test lamp illuminate?

--

Go to Step 43

Go to Step 10

10
  1. Connect a test lamp between the sunroof motor open control and motor close control circuits at the inline harness connector, module side of the sunroof motor.
  2. While observing the test lamp and depending on the position of the sunroof glass, press the sunroof switch to the available positions.

Does the test lamp illuminate with each command?

--

Go to Step 38

Go to Step 22

11

Did the reference voltage of the sunroof switch open signal circuit measure near the specified value?

B+

Go to Step 12

Go to Step 13

12

Measure the reference voltage of the sunroof switch close signal circuit to a good ground.

Did the reference voltage of the sunroof switch close signal circuit measure near the specified value?

B+

Go to Step 15

Go to Step 28

13

Measure the reference voltage of the sunroof close signal circuit at the sunroof switch harness connector to a good ground.

Does the voltage measure near the specified value?

4.5-5.5 V

Go to Step 18

Go to Step 14

14
  1. Disconnect the sunroof module harness connector that has the RAP supply voltage circuit.
  2. Measure the sunroof RAP supply voltage circuit at the sunroof module harness connector to a good ground.

Does the voltage measure near the specified value?

B+

Go to Step 37

Go to Step 33

15

Measure between the sunroof RAP supply voltage circuit and the ground circuit at the sunroof module harness connector.

Does the voltage measure near the specified value?

B+

Go to Step 37

Go to Step 40

16

Measure the resistance between the sunroof switch open signal and close signal circuits. Refer to Circuit Testing in Wiring Systems.

Does the resistance measure near the specified value?

OL

Go to Step 43

Go to Step 39

17

Did the reference voltage of the sunroof close signal circuit measure near the specified value?

B+

Go to Step 20

Go to Step 19

18

Test for an open, high resistance or short to ground in the sunroof switch open signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

Go to Step 37

19

Test for an open, high resistance or short to ground in the sunroof switch close signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

Go to Step 37

20

Test the sunroof switch close signal circuit for a short to B+. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

Go to Step 43

21

Test the sunroof switch low reference circuit for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

Go to Step 37

22

Did the test lamp illuminate with one command?

--

Go to Step 23

Go to Step 24

23

Is the sunroof glass in either the full open or full vent position?

--

Go to Step 44

Go to Step 43

24

Connect a test lamp between B+ and the sunroof motor open control circuit at the sunroof motor inline harness connector.

Does the test lamp illuminate?

--

Go to Step 25

Go to Step 27

25

Connect a test lamp between B+ and the sunroof motor close control circuit at the sunroof motor inline harness connector.

Does the test lamp illuminate?

--

Go to Step 43

Go to Step 26

26

Test the sunroof motor close control circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

Go to Step 37

27

Test the sunroof motor open control circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

Go to Step 37

28

Test the sunroof switch open signal circuit for a short to B+. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 45

Go to Step 43

29

Test for an open, high resistance or short to ground in the sunroof battery positive voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 45

Go to Step 30

30

Test both of the sunroof motor control circuits 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 45

Go to Step 31

31
  1. Disconnect the inline connector to the sunroof motor.
  2. Measure the resistance between the sunroof motor open control and close control circuits at the sunroof module harness connector. Refer to Circuit Testing in Wiring Systems.

Does the resistance measure near the specified value?

1-3ohms

Go to Step 41

Go to Step 32

32
  1. Replace SUNROOF fuse.
  2. Connect a test lamp between the sunroof motor control circuits at the inline harness connector to the sunroof motor, sunroof module side.
  3. Turn the ignition ON, with the engine OFF.
  4. Observing the position of the sunroof glass, press the sunroof switch to the available positions.

Does the test lamp illuminate?

--

Go to Step 44

Go to Step 43

33

Is the RAP supply voltage being supplied directly from the BCM?

--

Go to Step 34

Go to Step 35

34

Test for an open in the RAP supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 45

Go to Retained Accessory Power (RAP) Inoperative

35

Test for an open or short to ground in the RAP supply voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 45

Go to Retained Accessory Power (RAP) Inoperative

36

Inspect for a poor connection at the sunroof switch and harness connector. 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 45

Go to Step 42

37

Inspect for a poor connection at the sunroof module. 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 45

Go to Step 43

38

Inspect for a poor connection at the sunroof motor. 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 45

Go to Step 44

39

Repair a short between the sunroof switch open signal and close signal circuits. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 45

--

40

Repair the ground circuit of the sunroof module for an open or high resistance. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 45

--

41

Repair the short between the sunroof motor open control and close control circuits. Refer to Wiring Repairs in Wiring Systems.

Did you complete the replacement.

--

Go to Step 45

--

42

Replace the power sunroof switch. Refer to Sunroof Switch Replacement .

Did you complete the replacement?

--

Go to Step 45

--

43

Replace the sunroof module. Refer to Power Sunroof Module Replacement .

Did you complete the replacement?

--

Go to Step 45

--

44

Replace the sunroof motor. Refer to Power Sunroof Motor Replacement .

Did you complete the replacement?

--

Go to Step 45

--

45
  1. Turn OFF the ignition.
  2. Reconnect all previously disconnected components.
  3. Replace the SUNROOF fuse, if necessary.
  4. Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3