Source reference 2003-03-01

Manufacturer communication — 2003 GMC YUKON

Reporter type: Manufacturer

Vehicles as recorded

2003 GMC YUKON This vehicle's overview →

What the manufacturer’s document says

normal characteristic (no repair) ・ names this vehicle

Applies to

The condition affects some 2003 Silverado, Suburban, Tahoe, Avalanche, Sierra, Yukon, Denali, Escalade and EXT vehicles.
the passage
This condition affects some 2003 Silverado, Suburban, Tahoe, Avalanche, Sierra, Yukon, Denali, Escalade, and EXT vehicles.

Fault

A buzz that can be heard and felt comes from the accelerator pedal area on the first acceleration after starting, only the first time the vehicle reaches approximately 10 mph (16 kph).
the passage
Owners may experience a buzz noise which can be heard and felt, from the accelerator pedal area on the first acceleration after starting the vehicle. It will occur only the first time the vehicle reaches approximately 10 mph (16 kph) after start-up.
It does not occur again until the key is cycled off then on, and it may coincide with the 1-2 shift of the automatic transmission.
the passage
It will not occur again until the key is cycled off then on. Based on the driving habits of the owner, the condition may occur at approximately the same time as the 1-2 shift of the automatic transmission.

Finding the cause

Possible causes

The noise is the Supplemental Brake Assist (SBA) performing a self-test; the SBA, mounted to the brake vacuum booster canister, is new for 2003 and supplies vacuum to the brake booster if vacuum is low or lost.
the passage
This noise is caused by the Supplemental Brake Assist (SBA) performing a self-test. The SBA, which is mounted to the brake vacuum booster canister, is new for 2003 and provides vacuum for the brake booster in case of low vacuum or vacuum loss.

Correction

Caution

This is a normal condition and no repair should be attempted.
the passage
This is a normal condition and no repair attempts should be made.
The SBA is used only on vehicles with vacuum brake boosters, not on vehicles with Hydra-Boost brake systems.
the passage
The SBA is used only on vehicles equipped with vacuum brake boosters and is not used on vehicles equipped with Hydra-Boost brake systems.

What is needed

Parts and materials: Not stated
Labor time: Not stated
Special tools: Not stated
Scan tool: Not stated

Only what the technical documents state. "Not stated" does not mean not needed.

Compiled by reading the full text of the document; each point stands on the passage shown. Check the document itself, linked below, before working on a vehicle.

Stated content

Communication summary
アクセルペダルのバズ音と振動この状態は、一部の 2003 Silverado、Suburban、Tahoe、Avalanche、Sierra、Yukon、Denali、Escalade、EXT に該当する。所有者は、車両を始動した後の最初の加速時に、アクセルペダル付近から、聞こえるとともに体に感じるバズ音を経験することがある。始動後、車両が最初におよそ 10 mph (16 kph) に達したときにだけ発生する。キーをいったんオフにしてからオンにするまで、再び発生することはない。所有者の運転のしかたによっては、オートマチックトランスミッションの 1-2 シフトとほぼ同じタイミングで発生することがある。この音は、Supplemental Brake Assist (SBA) がセルフテストを行うことで生じる。SBA はブレーキバキュームブースターのキャニスターに取り付けられており、2003 年からの新しい装備で、負圧が低いときや負圧が失われたときにブレーキブースターへ負圧を供給する。これは正常な状態であり、修理を試みてはならない。 SBA はバキューム式ブレーキブースター装着車にだけ使われており、Hydra-Boost ブレーキシステム装着車には使われていない。 Machine translation (unreviewed)
Accelerator Pedal Buzz and Vibration This condition affects some 2003 Silverado, Suburban, Tahoe, Avalanche, Sierra, Yukon, Denali, Escalade, and EXT vehicles. Owners may experience a buzz noise which can be heard and felt, from the accelerator pedal area on the first acceleration after starting the vehicle. It will occur only the first time the vehicle reaches approximately 10 mph (16 kph) after start-up. It will not occur again until the key is cycled off then on. Based on the driving habits of the owner, the condition may occur at approximately the same time as the 1-2 shift of the automatic transmission. This noise is caused by the Supplemental Brake Assist (SBA) performing a self-test. The SBA, which is mounted to the brake vacuum booster canister, is new for 2003 and provides vacuum for the brake booster in case of low vacuum or vacuum loss. This is a normal condition and no repair attempts should be made. The SBA is used only on vehicles equipped with vacuum brake boosters and is not used on vehicles equipped with Hydra-Boost brake systems.
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Source

Source: GM TechLink
Source reference: 2003-03-01
Received by source: 2003-03-01
Incident date: Unknown

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