2008 Chevrolet Uplander • 54,000 miles

I had a growl in the front end and found that the front wheels had some play in them so I decided replace front wheel bearings before a long trip. Installed new hub assemblies and went on trip. On the way home I ran over a tire tread and it knocked out my left front tire pressure monitor, but it reset after I shut the van off at the next stop(and hasn't been an issue since). I don't know if the tire tread I hit has anything to do with this problem or not. After about 1500 miles on the new hubs I started getting the "service abs, t.C, and stab. Cont." Messages. Had the guys at autozone read the code and it said "front left speed sensor circuit fault". Put old hub back on and message light stayed away for a coulple weeks and then came back. I then traced abs wire harness from speed sensor to main harness at engine and saw no damage to it, I even pulled the pins out of the connector and they were still connected tight. Service messages are still coming up and traction control kicks in for no reason sometimes. I can not find anything wrong with harness or connector hopefully you can point me in the right direction. Any help would be greatly appreciated.
November 22, 2011.

The tire tread probably knocked the left front wheel speed sensor out of alignment.

Before beginning vehicle diagnosis, the following preliminary inspections/tests must be
performed: 1.
• Ensure that the battery is fully charged. Refer to Battery Inspection/Test.
• Ensure that the battery cables are clean and tight.
Inspect for any open fuses. Refer to Power Distribution Schematics and Electrical
Center Identification Views.

Ensure that the grounds are clean, tight, and in the correct location. Refer to Ground
Distribution Schematics and Harness Routing Views.

Inspect the easily accessible systems or the visible system components for obvious
damage or conditions that could cause the concern. This would include checking to
ensure that all connections/connectors are fully seated and secured.

Inspect for aftermarket devices that could affect the operation of the system. Refer to
Checking Aftermarket Accessories.

• Search for applicable service bulletins.
If the preceding inspections/tests resolve the concern, go to Diagnostic Repair
2. Install a scan tool. Verify that the scan tool powers up.
? If the scan tool does not power up, refer to Scan Tool Does Not Power Up.
Ignition ON, Engine OFF, verify communication with all of the control modules on the vehicle.
Refer to Scan Tool Does Not Communicate with Class 2 Device for information on the
modules you should expect to communicate.
If the scan tool does not communicate with one or more of the expected control modules,
refer to Scan Tool Does Not Communicate with Class 2 Device.
4. Verify the following DTCs are not set: U1040 or U1064
? If either of the DTCs are set, refer to DTC U1001-U1254.
IMPORTANT: Open the drivers door to ensure retained accessory power mode
(RAP) is inactive during this test. The engine may start during
this test. Turn the engine OFF as soon as the crank power mode
has been observed.
Access the Power Mode parameter on the scan tool. Verify the power mode parameter matches
all the ignition switch positions. Refer to Power Mode Description and Operation for
information on the power mode states that correspond to each ignition switch position.
If the power mode parameter does not match the ignition switch position for all ignition
switch positions, refer to Power Mode Mismatch.
Ignition ON, view the security indicator. The security indictor should not remain ON after the
vehicle bulb check has completed.
If the security indicator remains on after the bulb check, refer to Diagnostic Trouble
Code (DTC) List - Vehicle and diagnose any of the following theft deterrent DTCs set
as current: B2960, B3055, P1626, P1630, or P1631.
7. Attempt to start the engine. Verify that the engine cranks.
VEHICLE DIAGNOSTIC INFORMATION -2008 Chevrolet Uplander Page 1 of 2
? If the engine does not crank, refer to Symptoms - Engine Electrical.
8. Attempt to start the engine. Verify the engine starts and idles.
? If the engine does not start and idle, refer to Engine Cranks but Does Not Run.
IMPORTANT: Do not clear any DTCs unless instructed to do so by a diagnostic
IMPORTANT: If any DTCs are Powertrain related DTCs, select Capture Info in
order to store the DTC information with the scan tool.
Use the appropriate scan tool selections to obtain DTCs from each of the vehicle modules.
Verify there are no DTCs reported from any module.
If any DTCs are present, refer to Diagnostic Trouble Code (DTC) List - Vehicle and
diagnose any current DTCs in the following order: ?
1. DTCs that begin with a U.
Any of the following: B1000, B1001, B1004, B1007, B1009, B1013, B1290,
C0550, P0601, P0602, P0603, P0604, P0606, P0607, P060D, P062F, or P2610.
3. Any of the following: B1327, B1328, B1420, C0899, C0900, P0562, or P0563.
4. Component level DTCs.
5. System level DTCs.
6. Any remaining DTCs.
If the customer concern is related to inspection/maintenance (I/M) testing, refer to
Inspection/Maintenance (I/M) System Check.
If none of the previous tests or inspections addresses the concern, refer to Symptoms -

Nov 22, 2011.
But why would I still get trouble code after putting old hub back on when it didn't have problem before?

Nov 22, 2011.
Have you been able to figure this out yet?

Dec 5, 2011.