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1989 - 1991 Corvette: Service Bulletin: New Delco-Loc II Setting Procedure and Information

Subject: NEW DELCO-LOC II SETTING PROCEDURE & INFORMATION
Model and Year:
1989-91 CAMARO AND CORVETTE
1990-91 U-VAN (APV)
Source: Chevrolet Service Bulletin
Bulletin Number: 91-138-9A - (12/31/1990)

TO: ALL CHEVROLET DEALERS

THIS BULLETIN CANCELS AND SUPERSEDES DEALER SERVICE BULLETIN NO. 91-100-9A, DATED OCTOBER 1990. THE BULLETIN NUMBER IN THE FIRST PARAGRAPH HAS BEEN CORRECTED. ALL COPIES OF 91-100-9A SHOULD BE DISCARDED.

Application Information: F, Y Cars, U Van

The following information updates all existing Service Manual information.

The procedures below explain how to operate the Delco LOC 11 security system. This includes entering and removing customer codes, unlocking the radio, obtaining the factory display code, and obtaining the factory backup code.

General Information:

Different model radios use different buttons to set the codes into the radio. To determine which two buttons to use, determine if the radio has a seek button, a seek up/down button, or no seek button at all.

If the radio has a seek button, use seek and scan to set the codes as described below.

If the radio has a seek up/down button, use seek up/down and tune up/down to set the codes and substitute these buttons for seek and scan in the procedures below.

If the radio has no seek button, use tune down and tune up to set the codes and substitute these buttons for seek and scan in the procedures below.

Different model radios have different functions attached to the radio presets. Below is the' present configuration of dual functions depending on the radio having a seek button, seek up/down or no seek button at all.

SEEK BUTTON: Presets 1 (PREV), 2 (NEXT), 3 (REV), 4 (FF), 5 (COMP)

SEEK UP/DOWN: Presets 1 (PREV), 2 (NEXT), 3 (REV), 4 (FF), 5 (COMP)

NO SEEK: Presets 1 (REV), 2 ((FF), 3 (COMP), 4 (REPT) 5 (SRCH), 6 (SCAN)

RADIO DISPLAYS:

"LOC" Means the radio is locked and there is a customer code stored in the radio.

"InOP" Means too many wrong codes have been entered and the radio must be left powered up for 1 hour with battery and ignition applied before 3 more attempts can be made.

"SEC" Means there is a customer code stored but the radio is unlocked.

"__" Means there is no customer code stored and the radio is unlocked.

"rEP" Means you have entered your customer code once, and the radio now wants the code repeated again to verify you entered the correct code the first time.

PROCEDURE:

A. TO UNLOCK RADIO - From 'LOC' display Mode on Power Up After Battery Power is Removed

Display comes up "LOC" 'LOC'

1 . Press the set button '000'

2. Set the first digit (0-9) of your code with the seek button. '100'

3. Set the next two digits (0-99) of your code with the scan button. '123'

4. Press the am-fm button to enter the first three digits. '000,

5. Again, use seek to set the 4th digit (0-9) of your code. '400'

6. Set the last two digits (0-99) of your code with the scan button. '456'

7. Press the am-fm button to enter the last 3 digits of your code.

Radio is unlocked and clock is displayed. '1:00'

IMPORTANT: If the backup code(s) received from the computer do not unlock the radio, another possible code is all O's. When entering the code after step 1 above, press the AM-FM button twice.

IMPORTANT: If 8 unsuccessful tries are made to unlock the radio, the display will return to the 'LOC' display, but when you press the set button, 'InOP' will be displayed. This means the radio must be left powered up for 1 hour with battery and ignition applied before any more attempts to unlock the radio can be made. Anytime'InOP' is displayed, 3 more attempts will be allowed after the 1 hour waiting period with battery and ignition applied.

B. TO REMOVE CUSTOMER'S CODE-Deactivate Theft Deterrent From Unlocked Mode, Deterrent Activated.

1. With the radio off, hold in presets 1 and 4 for about 4 seconds until the display changes to 'SEC' SEC.

IMPORTANT: If the display changes to '-', the theft deterrent is already deactivated.

2. Press the set button '000'

3. Set the first digit (0-9) of your code with the seek button. '100'

4. Set the next two digits (0-99) of your code with the scan button. '123'

5 . Press the am-fm button to enter the first three digits. '000'

6. Again, use seek to set the 4th digit (0-9) of your code. '400'

7. Set the last two digits (0-99) of your code '456' with the scan button.

8. Press the am-fm button to enter the last 3 digits of your code. '1:00'

Theft deterrent is deactivated and '-' then clock is displayed '1:00'

C. TO ADD CUSTOMER'S CODE-Set User Code (activate) From Unlocked Mode, Deterrent Deactivated.

1. With the radio off, hold in presets 1 and 4 for about 4 seconds until the display changes '__' to '__'

IMPORTANT:If 'SEC' is displayed, the theft 'SEC' deterrent is already activated. This means the old code must be removed first before entering a new code.

2. Press the set button. '000'

3. Set the first digit (0-9) of your code with the seek button. '100'

4. Set the next two digits (0-99) of your code with the scan button. '123'

5 . Press the am-fm button to enter the first three digits. '000'

6. Again, use seek to set the 4th digit (0-9) of your code. '400'

7. Set the last two digits (0-99) of your code with the scan button. '456'

8. Press the am-fm button to enter the last 3 digits of your code. 'rEP'

9. When 'rEP' then '000' are displayed, repeat '000' Steps 3 through 8 of this procedure to enter your code again before the display changes back to clock. This confirms your customer code, activates the theft deterrent, and after step 8 displays the 'SEC' to show the theft deterrent 'SEC' has been activated. Any time battery power is cycled and ignition is applied the display will show 'LOC' and need to be unlocked by either 'LOC' your customer code or the factory backup code.

D. To display Radio Display Code (Scrambled Backup Code)

IMPORTANT: In order to display this code, the radio should be in 'LOC' mode or have 'SEC' displayed before proceeding.

1. Press and hold presets 2 and 3 for about 8 seconds until the first 3 digits of the display code are displayed. '123'

2 . Please write the number down. '123'

3 . Press the am-fm button. The second 3 digits of the display code are displayed. '456'

4. Please write the numbers down. '456'

This display code can be unscrambled to get the factory backup code to unlock the radio by calling the Delco Phone number and entering the display code along with your authorization code.

E. To obtain Factory Backup Code After Obtaining Display Code (Step D)

1. After obtaining the display code in Step 'D' call 1-800-537-5140 (U. S. and Canada) or (317) 451-8965. (You will need your six digit dealer code number).

2. When the computer prompts, using a Touchtone (TM) telephone, enter your 6 digit dealer code, then press *. For example, if your dealer code is 213063, then you would enter 213063 *.

3. When prompted, enter the 6 digit radio display code, then press *. The computer will respond with the factory backup code. Please write it down. The computer may give you two possible codes. If the first code does not unlock the radio per step 'A', then use the second code. On some models another possible backup code is O's. Refer to step 'A' to use these factory backup codes.

F. To Change Customer's Code

IMPORTANT:To change the customer's code the radio must be unlocked and no customer code stored in the radio. The radio will display clock '1:00' when unlocked. To determine if there is a customer code stored or not, press and hold presets 1 and 4 until the display changes. If 'SEC' is displayed, there is a customer code stored. If '-' is displayed, there is no code stored.

Once the radio is unlocked and the old customer code is removed by following parts A and B, enter the new customer code by following step C.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.

© Copyright General Motors Corporation. All Rights Reserved

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