Sqiweeky front end - 2002 GMC Envoy

The front impact sensor is located under the vehicle, towards the center/driver's side. Best access is from under the vehicle with the front air deflector removed.

• Remove the front air deflector.
• Remove the connector position assurance (CPA) (5) from the front end sensor wiring harness connector (4).
• Disconnect the front end sensor wiring harness connector (4) from the front end sensor (1).
• Through the access hole located in the bottom of the lower tie bar, loosen the front end sensor mounting fastener (3).

IMPORTANT: The front end sensor mounting fastener (3) has left handed threads.

• Remove the front end sensor (1) from the lower tie bar by lifting upward and sliding rearward out of the key hole slot (2).

sensor that was replaced per the code scanner , That's where you made your mistake . No code tell's you to replace a part without testing . Did you do factory trouble shooting per code diagnostic testing procedures ?
The inflatable restraint front end sensor utilizes a unidirectional 2-wire circuit. The front end sensor modulates current on the interface to send ID, state of health, and deployment commands to the inflatable restraint sensing and diagnostic module (SDM). The SDM serves as a power source and a ground for the front end sensor. When the ignition is turned ON and input power from the SDM is first detected, the front end sensor responds by performing internal diagnostics and sending an ID to the SDM. The SDM considers the ID to be valid if the response time is less than 5 seconds. The front end sensor continually communicates status messages to the SDM, which determines if a fault is present in the front end sensor circuit. When a fault is detected, the SDM may reset the front end sensor up to 2 times by removing and reapplying power to it. If the fault is still present, the SDM will set a DTC.

B0091 00
• The front end sensor has been shorted to voltage, open, or shorted to ground.
• The front end sensor current has been above 23 mA for longer than 5 milliseconds.
• The SDM has not received a message from the front end sensor for more than 375 milliseconds.

Circuit/System Testing
Important: When removing the connectors, inspect for damage or corrosion. Damage or corrosion to the following requires repair or replacement of the affected component/connector:
• Front end sensor
• SDM module
• Front end sensor wiring harness connector
• SDM wiring harness connector
Ignition OFF, disconnect the harness connector at the front end sensor and the SDM.
Ignition ON, test for less than 1 volt between the front end sensor signal circuit terminal 2 and ground.
? If greater than the specified range, test the signal circuit for a short to voltage.
Ignition ON, test for less than 1 volt between the front end sensor low reference circuit terminal 1 and ground.
? If greater than the specified range, test the low reference circuit for a short to voltage.
Test for infinite resistance between the front end sensor signal circuit terminal 2 and ground.
? If less than the specified value, test the signal circuit for a short to ground.
Test for infinite resistance between the front end sensor low reference circuit terminal 1 and ground.
? If less than the specified value, test the low reference circuit for a short to ground.
Test for less than 1 ohm between the SDM signal circuit terminal 38 and the front end sensor circuit terminal 2 harness connector.
? If greater than the specified range, test the signal circuit for an open/high resistance.
Test for less than 1 ohm between the SDM low reference circuit terminal 36 and the front end sensor circuit terminal 1 harness connector.
? If greater than the specified range, test the low reference circuit for an open/high resistance.
If all circuits test normal, test or replace the front end sensor.
Reconnect all SIR components. Ignition ON, verify the DTC is not set as current.
? If the DTC resets as current, replace the SDM.

Wheel bearing? If you turn left and it gets louder. It is the right wheel bearing. And vice versa.

not sure what you mean need more details. if there is a shake in the front end when car is running check to see if the motor is moving at all wile running. i have the same car and the shake turned out to be a broken motor mount on the front of the motor

Hi there:
DTC B0100 - Electronic Front End Sensor 1 Performance

The following can cause an intermittent condition:

• A short between the front end sensor signal and low reference circuits
• High or low resistance in the front end sensor signal and low reference circuits
• Inspect the front end sensor signal and low reference circuits carefully for cutting and/or chafing
• Verify that the correct front end sensor is installed in the vehicle

Hope helps.

FRONT END SHIMMY AND SHAKING COULD HAVE A TIRE OUT OF BALANCELOOSE OR WORN WHEEL BEARINGS, WORN OUT BALL JOINTS,WORN OUT TIE ROD ENDS, FRONT END NEED ALIGNMENT.BRAKE ROTOR WORN OUT OR WARPED, MANY THINGS WILL CAUSE FRONT END TO SHAKE SHIMMY.

Nope.... best solution is find another Elantra and take the front end apart for comparison.

Yep....agreed. Ball joints are bad....if you had done maintenance on the front end steering or suspension system, you need a front end alignment. But, you definitely have issues with the suspension system.

Tierod, ball joints, struts....could be a lot of things.

Let us know what has been done to the front end.

Couple of checks , mud in front rims will give you a wobble. Front tire cord seperation or loose wheel nuts. , Wore out tie rod end, front wheel bearing play, or a weight has fallen off the rim and it needs balancing. If it is vibrating your steering wheel, have the front end looked at right away.

Check the motor mounts, they tend to go bad on this vehicle. If they are ok, you may have a inner cv joint that is binding.

Bret