Driver Information Center (DIC) Reduced Brake Power Message, Reduced Vacuum Boost (Inspect/Replace Intake Manifold and Recalibrate the Instrument Panel Cluster (IPC))

Some customers may comment on a "Reduced Brake Power" message on the DIC.

It is possible that a very small number of 2002 and 2003 model year vehicles may have a restriction in the vacuum booster port on the intake manifold. On the 2003 model year, only the IPC calibration is the cause of the DIC message.

Important: Only inspect suspect vehicles built between June 13, 2002 and August 9, 2002.

Follow the service procedure below to diagnose and correct this condition.

1. Open the hood and install fender covers.
2. Loosen the engine sight shield bolt. The bolt should stay in the shield.
3. Remove the engine sight shield from the sight shield retainer.



4. Inspect the left front corner of the intake manifold for a "C" with a circle around it (2).

•	If the intake manifold DOES have a "C" (2) on it, continue with step 5.

•	If the intake manifold DOES NOT have a "C" (2) on it, continue with step 19.

5. Disconnect the accelerator control cable clip from the engine sight shield retainer.
6. Disconnect the cruise control cable clip from the retainer if equipped.
7. Remove the engine sight shield retainer bolts and the retainer if equipped.
8. Inspect rear center of the intake manifold just below the recycle symbol for "MADE IN CANADA" (2).

•	If the intake manifold DOES have "MADE IN CANADA" (1) on it, continue with step 9

•	If the intake manifold DOES NOT have "MADE IN CANADA" (1) on it, continue with step 16.




9. Locate the vacuum booster port connector (1) on the left rear of the intake manifold.
10. Gently pull out on the vacuum booster hose (2).
11. With two fingers, push in the vacuum booster port connector lock ring (3) while gently pulling out on the vacuum booster hose (2).

Important: 

•	DO NOT force the drill bit into the vacuum booster intake port.

•	If the vacuum booster intake port is restricted, DO NOT attempt to remove the restriction with the drill bit.

•	If the restriction is removed with the drill bit, the material from the restriction may cause internal engine damage.

•	If the vacuum booster port is restricted, the intake manifold must be replaced.

12. Inspect the vacuum booster intake port with a 8.7 mm (11/32 in) drill bit, maximum length of 127 mm (5 in).
13. Insert the drill bit approximately 63.5 mm (2.5 in) into the vacuum booster intake port.

•	If the vacuum booster intake port IS restricted, continue with step 14.

•	If the vacuum booster intake port IS NOT restricted, continue with step 15.

14. Replace the intake manifold. Refer to Intake Manifold Replacement (SI Document ID # 753666).
15. Reinstall the vacuum booster hose to the vacuum booster intake port by pushing to hose nipple into the connector.
16. Install the engine sight shield retainer and the bolts.

Tighten
Tighten the engine sight shield retainer bolts to 5  N·m (44 lb in).

17. Install the cruise control cable clip to the retainer.
18. Install the accelerator control cable clip to the retainer if equipped.
19. Install the engine sight shield to the retainer if equipped.

Tighten
Tighten the engine sight shield bolt to 10  N·m (89 lb in).

20. Start the engine and fully apply the brakes four or five times in order to ensure a "good" brake pedal.

Recalibrating the IPC (2003 Model Year Vehicles)

1. Vehicles Built Prior To the following VIN Breakpoints

•

3G104569

•

3E117608

•

31118369

•

3Z120443

•

3R107568

•

3J101720

2. Plug in Tech 2.
3. Set the parking brake and turn the ignition ON with the engine off.
4. Reprogram the IPC following normal SPS procedures (TIS Version 9 released August 2002 or newer).
5. After reprogramming the IPC, start the vehicle and fully apply the brakes four to five times in order to ensure a "good" brake pedal and that there are no messages on the DIC.

Important: 

The Owner's Manual Must Be Replaced After The IPC Is Recalibrated.

Parts are currently available from GMSPO.

For vehicles repaired under warranty, use: