GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1998 🢒 Monte Carlo 🢒 Body and Accessories 🢒 Theft Deterrent 🢒 SECURITY Indicator Always On or Flashing

Step

Action

Value(s)

Yes

No

1

Did you perform the Vehicle Theft Deterrent System Check?

--

Go to Step 2

Go to Vehicle Theft Deterrent (VTD) System Check

2
  1. Insert the ignition key into the J 35628-A .
  2. Turn on the J 35628-A .
  3. Read the key code shown on the display of the J 35628-A .

Does the J 35628-A display a key code value of 1 through 15?

--

Go to Step 3

Go to Step 8

3
  1. Write down the key code that is displayed on the J 35628-A .
  2. Turn off the J 35628-A .

    3. Important: This vehicle is equipped with the Supplemental Inflatable Restraint (SIR) system. Do not confuse the key detection CKT 2-way connector (CKT 1073 and CKT 1074) and the yellow 2-way SIR connector.

  3. Connect the J 35628-A .
  4. Insert the ignition key into the ignition key lock cylinder.
  5. Turn on the J 35628-A .
  6. Observe the display on the J 35628-A .

Does the J 35628-A display a key code value of 1 through 15?

--

Go to Step 4

Go to Step 9

4
  1. Disconnect the J 35628-A .
  2. Connect a J 39200 DMM.
  3. Measure the voltage by backprobing between B+ and the key detection CKT 2-way connector (CKT 1073 and CKT 1074) terminal B on the harness side.

Is the voltage within the specified range?

B+ (10-14 V)

Go to Step 5

Go to Step 10

5
  1. Turn the ignition switch to the LOCK position.
  2. Disconnect the theft deterrent module connector.
  3. Reconnect the key detection CKT 2-way connector (CKT 1073 and CKT 1074).
  4. Turn the ignition switch to the RUN position.
  5. Connect a J 39200 Digital Multimeter (DMM).
  6. Measure the voltage by backprobing between the key detection CKT 2-way connector (CKT 1073 and CKT 1074) terminal  A and the ground.

Is the voltage less than the specified value?

2 V

Go to Step 6

Go to Step 13

6

Use a J 39200 in order to measure the resistance by backprobing between the key detection CKT 2-way connector (CKT 1073 and CKT 1074) terminal A and the ground.

Is the resistance within the specified range?

∞

Go to Step 7

Go to Step 14

7

Use a J 39200 to measure the resistance between the theft deterrent module connector terminal B8 and the key detection CKT 2-way connector (CKT 1073 and CKT 1074) terminal A.

Is the resistance less than the specified value?

2ohms

Go to Step 17

Go to Step 15

8
  1. Clean the ignition key resistor pellet.
  2. Connect a J 39200 .
  3. Measure the resistance across the resistor pellet.
  4. Compare the resistance value of the pellet with the following values:
    5. • Nominal 402ohms (386-438ohms)
    • Nominal 523ohms (502-564ohms)
    • Nominal 681ohms (654-728ohms)
    • Nominal 887ohms (852-942ohms)
    • Nominal 1130ohms (1085-1195ohms)
    • Nominal 1470ohms (1411-1549ohms)
    • Nominal 1870ohms (1795-1965ohms)
    • Nominal 2370ohms (2275-2485ohms)
    • Nominal 3010ohms (2890-3150ohms)
    • Nominal 3740ohms (3590-3910ohms)
    • Nominal 4750ohms (4560-4960ohms)
    • Nominal 6040ohms (5798-6302ohms)
    • Nominal 7500ohms (7200-7820ohms)
    • Nominal 9530ohms (9149-9931ohms)
    • Nominal 11800ohms (11328-12292ohms)

Does the resistor pellet resistance value match the values listed above?

--

Go to Step 3

Go to Step 16

9
  1. Inspect for a poor connection at the ignition key lock cylinder resistor sensing contacts.
  2. If no problem is found replace the ignition key lock cylinder.

Is the repair complete?

--

Go to Step 4

--

10
  1. Disconnect the theft deterrent module.
  2. Connect a J 39200 DMM.
  3. Measure the resistance between the theft deterrent module harness connector terminal B7 and the key detection CKT 2-way connector (CKT 1073 and CKT 1074) terminal B.

Is the resistance less than the specified value?

2ohms

Go to Step 11

Go to Step 12

11

Inspect CKT 1550 for a poor connection or an open.

Is the repair complete?

--

Go to Step 5

--

12

Repair a poor connection or an open in CKT 1074.

Is the repair complete?

--

Go to Step 5

--

13

Repair a short to B+ in CKT 1073.

Is the repair complete?

--

Go to Step 6

--

14

Repair a short to ground in CKT 1073.

Is the repair complete?

--

Go to Step 7

--

15

Repair a poor connection or an open in CKT 1073.

Is the repair complete?

--

Go to Step 17

--

16

Replace the ignition key. Refer to Programming Additional Keys .

Is the repair complete?

--

Go to Step 8

Go to Step 17

17
  1. Turn the ignition switch to the LOCK position.
  2. Reconnect any connectors/components removed.

Is the repair complete?

--

Go to Vehicle Theft Deterrent (VTD) System Check

--