GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

  1. Connect a scan tool.
  2. Turn the Ignition ON
  3. Inspect the system for the PASS-Key® III module data.

Is PASS-Key® III module data present?

--

Go to Step 2

Go to Step 3

2

Using the scan tool, obtain PK3 module DTC's.

The following list is of possible DTCs that directly affect the PASS-Key® III system:

    • DTC B0686 - PASS-Key® III - Security System Indicator Circuit Range (Over Current)
    • DTC B0687 - PASS-Key® III - Security System Indicator Circuit Low
    • DTC B0688 - PASS-Key® III - Security System Indicator Circuit High
    • DTC B0689 - PASS-Key® III - Security System Indicator Circuit Open
    • DTC B1009 - PASS-Key® III - EEPROM Checksum Error
    • DTC B2955 - PASS-Key® III - Security System Sensor Data Circuit Malfunction
    • DTC B2960 - PASS-Key® III - Security System Sensor Data Incorrect But Valid

Are any PASS-Key® III DTC set?

--

Go to Step 17

3

Using the scan tool, obtain PCM data.

Is PCM data obtained?

--

Go to Step  4

Go to Data Link Communications System Check

4

Inspect for an open in CKT 1807 between S236 and the PK3 module terminal B.

Was a problem found?

--

Go to Step 5

Go to Step 6

5

Repair the open in CKT 1807.

Has the repair been made?

--

Go to Step 1

--

6

Inspect the PASS KEY fuse.

Is the fuse OK?

--

Go to Step 7

Go to Step 12

7

Inspect the PCM fuse.

Is the fuse OK?

--

Go to Step 8

Go to Step 13

8

Using a test light, backprobe the PK3 module connector at terminal A and ground.

Is the test light ON?

--

Go to Step  9

Go to Step 14

9

Using a test light, backprobe the PK3 module connector at terminal E and ground.

Is the test light ON?

--

Go to Step  10

Go to Step 15

10

Using a test light, backprobe the PK3 module connector at terminal E and terminal C.

Is the test light ON?

--

Go to Step  11

Go to Step 16

11

Inspect the PK3 module connector for proper connection. If connector is OK, Replace the PK3 module.

Has the repair been made and the system rechecked?

--

Go to Programming Theft Deterrent System Components

--

12

Inspect for a short to ground in CKT 3140.

Has the repair been made and the system rechecked?

--

Go to Step 1

--

13

Inspect for a short to ground in CKT 439.

Has the repair been made and the system rechecked?

--

Go to Step 1

--

14

Repair the following condition in CKT 3140.

    • a poor connection
    • an open

Has the repair been made and the system rechecked?

--

Go to Step 1

--

15

Repair the following condition in CKT 439.

    • a poor connection
    • an open

Has the repair been made and the system rechecked?

--

Go to Step 1

--

16

Repair the open in CKT 1550.

Has the repair been made and the system rechecked?

--

Go to Step 1

--

17

Turn the key OFF.

While observing the PASS KEY telltale, Turn the key ON.

Does the PASS KEY telltale illuminate for 2 seconds and then go OFF?

--

Go to Step 18

Go to Step 11

18

Turn the ignition key to START and then release to RUN.

Does the engine start and run?

--

System OK

Go to Step 19

19

Inspect CKT 229 for the following:

    • an open
    • a short to ground
    • a short to voltage

Is there a problem with the circuit?

--

Go to Step 20

Go to Step 11

20

Repair the fault in CKT 229.

Has the repair been made and the system rechecked.

--

Go to Step 1

--